Gallan, it might make a difference where you are, as well. Otherwise I would recommend a Presbyterian church. Just don’t be surprised when everything runs a little late. 
And you see people sleeping through the sermon (my dad does, when my parents bother to go to church, and he used to be a pastor.)
It’s been several years since I went, but I’m not sure if they even have the whole greet your neighbors thing, and if they do it’s a ‘hi’ and a handshake.
This is usually what I do when I attend a Catholic mass. I also don’t do the audience responses, as they usually involve expressing some kind of faith and I cannot legitimately do this. Depending on the song (and whether I remember the words) I may sing.
As others have said, a part of the service involves shaking hands with one’s neighbours and wishing peace upon them. It isn’t very complicated and it’s not something an unbeliever should have any problem with. I usually leave one or two dollars in the collection plate. I’ve never been bothered by anyone; church-going Catholics seem to be about letting people do their thing. And I’ve attended a Good Saturday mass in a small Italian church where I guess my not being from the place must have been obvious.
Now I feel I should try to go to other denominations’ religious services. I’ve only attended Catholic masses; I wonder what Protestant and Orthodox services (let alone services from other religions) look like.
When I was a child and going slightly more regularly to church, we could go get bread (regular bread which I suppose might have been blessed, but wasn’t considered the Body of Christ) while the adults were getting the Eucharist. This bread was distributed by teenagers from the congregation. Crossing one’s arms and being blessed by the priest isn’t part of my experience, I think I heard of it on this board.
As a nominal Jew, can you explain why someone might do this? I’d think if you were not partaking it would be simpler to just stay in your seat.
That’s interesting. I’ve observed it maybe half the time. If the parent feels the kids are old enough and can be trusted, they leave them behind in the pew (perhaps, if available, with an older sibling or another adult in their group who is not receiving communion). Otherwise the kids stand beside or behind the parent when the parent receives communion and just turn and walk off with the parent. Since the child neither holds out their hands or extends their tongue, they either get ignored or occasionally patted on the head by the priest or minister. There’s no special announced procedure or ceremony for them.
Only skimmed through the beginning, but another vote for Catholic. Or if your mom has a thing against Catholics (I know some do) maybe Episcopal, since they are sorta similar? I never went to one, but I’m guessing.
Catholics will not hassle you. I went under similar circumstances for a friend, and I didn’t believe him when he swore no one would talk to or even look at me (except for some part of the service where you shake hands, but it’s no biggie). I mean, I live in Mississippi. People DO NOT keep their religion inside their hearts or whatever. But, he was totally right. Not a word, not a glance.
I even talked to the priest afterwards and got a tour of the big sanctuary (my aforementioned friend made all the stained glass windows) and I told the priest I wasn’t Catholic, and implied I was an atheist, and he just smiled and said I was always welcome or something like that. Totally no pressure.
There are certain rules about who may or may not receive communion. You must have made your official first communion, you must not be in a state of grave sin, and you must have fasted for an hour before mass.
I believe some parishes (arch-dioceses?) have adopted this custom so that someone who is not prepared to receive communion for whatever reason can (no questions asked) feel like they are part of the community and not feel left out. (Perhaps it’s meaningful to you to be able to walk up to the alter with your family.) And they get a blessing, too! If they prefer, they can just stay in their seat (which most do).
At the mass I went to, the priest would give you a blessing. My friend encouraged me to do that, but I thought it seemed silly (I’m an atheist!) and also I hate getting in front of people, and I was already WAY out of my comfort zone, so I skipped it. I was the only person who didn’t go up, and again, no one batted an eye.
Don’t go to my church (ELCA Lutheran) if you want to be left alone. At least half a dozen people will lunge at you to welcome you, introduce themselves, invite you to stay afterwards for coffee and a cookie, and generally try to make you feel we are glad you are there.
If you do decide to offer yourself up as fresh meat to the sharks, just mention that you covet prayer for your mom, and we will be on that like stink on shit. That’s the kind of thing we live for, literally.
Don’t worry if you don’t sing along - half the congregation is too deaf to hear the tune anyway. Or just sit by me - I generally try to make up in volume what I lack in talent and everybody else has tuned out all noise from my pew years ago.
The ushers will hand you a piece of paper with the Order of Service on it, so you can follow along. The hymns are projected up on the screen at the front.
Don’t go up for communion (the Eucharist - the bread and wine) if you are not a baptized believer. The minister will generally make an announcement to that effect before distribution.
Best wishes to your mom - tell her, if you like, that there is a Doper praying for her as a new Christian and fellow member of the Body of Christ.
Regards,
Shodan
Seems that the Mom in question is definitely going to a protestant (and not Episcopalian) church, so that’d be the way I’d go. Mainline, Presbyterian, Lutheran, Methodist.
Were I in this situation, I’d pick a church close by and call the pastor. Tell him or her exactly what you’ve told us: you’re an atheist but your mom is dying and has recently turned to the church and you’d like to attend a couple of services to be able to better relate to her now, and you’d like to do this on your own terms without being singled out or proselytized because you’re not a seeker in the traditional sense and not comfortable with the trappings of the church.
Ask the pastor if they think that their church is a place where you can come on your terms. They should be honest with you about the tenor of their congregation and whether or not they do a “will all our esteemed visitors please stand so that we can give you a visitor packet and a warm welcome” kind of moment in the midst of the service or anything like that. If they hem and haw with you or can’t quite answer your concerns about how well you can fulfill your goal in their church, then it’s not the place for you to try.
I caution about megachurches. The last one I attended (before my conversion to Judaism) actually had printed nametags for all those in attendance on Sunday mornings, to “further fellowship.” Visitors were singled out on sight by the greeters at the sanctuary doors because of their lack of nametag so then someone would immediately dispatched to propel newcomers (damn near forcibly) to the visitors’ station where they’d be asked to fill out cards with their names and all their contact information and a special bright yellow nametag and duotang folder stuffed 3/4" thick with visitor materials would be given to them. Some megachurches are conscious of the critique that 2,000+ people in a service makes it easy to get “lost” in the flow and are quite proactive about no one slipping through the cracks, even if they want to.
No church is so big that Baby Jesus won’t notice you!
Summary:
Churches are all different. It’s hard to know before you go in whether they’re going to harass you or not.
The older and more formal the denomination, the less chance of harassment, but the better chance of sticking out because you don’t go with the flow of the service as well.
Best overall bets to avoid human contact in ANY CHURCH (my qualifications: many many years in 5 or so different denominations and various individual churches with a social anxiety disorder):
Arrive about 5 to 10 minutes late (call it more like 20 in the South, or with very laid-back denominations) to avoid “greeters,” offers of coffee, and church bulletins thrown at you when you come in. (Special note - there is usually a card table or end-table situated by the door for late-comers to grab a service bulletin on their way in - GET ONE so you know when the following moments will occur, and you can prepare ahead of time.
When the “fellowship moment” or “passing the peace” or “peace of God” section comes up (check your bulletin), remain seated with your head bowed as if praying. Either that or nod and smile with your arms crossed, mouthing something about germs. Ditto for communion or any other social moment. If in doubt, hang back and look around the room - if anyone else is staying seated or not participating, you can do the same.)
When the service seems to be winding down (check your bulletin to be sure), slip out during the closing prayer or last hymn to avoid pastor greeting lines or “overly welcoming” church people who noticed you during the service.
Once you become familiar with a particular church, the last bit can be altered (if you want to stay through the whole thing), to substitute slipping out the kitchen or side or choir door. Anyone there is busy and if you walk like you know what you’re doing, they will leave you alone while you GTFO of Dodge.
However, leaving early does get you out of the parking lot faster, which is a not insignificant concern with some really big churches.
I would say avoid Catholic, Lutheran, and Episcopalian because there is so much going on for you to look out of place. Believer or not, taking communion is making a statement. That you are an athiest doesn’t mean you are willing to make false statements. Avoid large, new churches that do a lot of advertising. They have gotten where they are by attention to visitors.
Given the circumstances we’ve all overlooked the obvious. Simply find a church that either streams its service live online or puts the sermon up after the service. If you’re lucky, maybe your mom’s church already does it. Then you can discuss what you saw or heard with her without ever actually stepping foot inside the building.
Sorry if this is a little off topic: Until today I always thought this was just an innocent custom that some churches practice and some don’t. But after reading this, I now see that it now seems to be quite a contentious issue that you really should avoid bringing up with any armchair cannon lawyers.
I know your question was addressed to the OP, but I am going to answer my way anyway. 
As an atheist, why do I go to church? Because it is an excellent way for someone (me) that has trouble socializing to socialize! I won’t give detailed suggestions about the denomination I attend because you’d have to switch countries to attend (United Church of Canada), but the ones I have attended are definitely NOT pushy about religion (although I do admit I haven’t told any ministers about my lack of belief :D). I’m sure you could find something similar south of the border as long as you weren’t in the Bible Belt.
Let me also add that there is a point just before communion where you turn to those people around you and shake hands, and say “Peace be with you.” Probably shaking hands with up to a dozen people in a time span of 30-45 seconds in a crowded church at most.
Yeah, you get people who are totally fixated on the rules, church is funny that way. 
I once had a priest who, during his sermon, danced a bit at the altar. No big thing, it had something to do with his sermon - it wasn’t as if he played music and danced, he was making some comparison between a dance step and something… following the logic of sermons have never been my strong point.
Well! Let’s just say that created a *bit *of a fuss. Letters were written to the bishop, newspaper, blogs were posted, etc. So the very next Sunday the same priest, Father Michael, at the end of the Mass called out these people by name, told them they ought to be ashamed at themselves for thinking that merely following the rules meant you were following God, then called all the children (8 and under) to the altar whereupon the choir launched into the hymn Lord of the Dance and Father Michael took two kids by their hand, started dancing, and the rest of the kids caught on (my daughter was among them).
They danced the entire song.
It was awesome, and he did the same thing for all four masses that Sunday.
Ahh… I;ve been to lots of churches … my Mother, in her ways, took me on a tour of churches throughout my younger years and up until my and my thirties, all through my psychotic breeaks, and supposed “treatment” buy the psychiatric/psycho-pharmaceutical community, various denominations of wedding quasi services, and many Catholic, lutheran, Protestant family members ( my Aunt and Uncle who are devoutly religous, but tend to be easily misled by cultic religions and sects.) although we weren’t “religous”. My parents “believed” in God, but we were never pious and pretty schizo about the denominations that we attended… Mostly you can expect to be greeted with various degress of enthusiasm with a head nod, a suspicious, glance , or a handshake… of course this is relative to the size of the church… the larger is somewhat less personable and easier to blend in. But you will be considered a “stranger” in most, but welcome. Foillow the program, Leave a donation, refuse commitment at the end of the service, thank them, and walk out the door. Just common courtesy of attending any “club” or “group” meeting.
One thing you likely have figured out is that churches are not peas in a pod. Several of us have mentioned lifeless singing. Norm, but exceptions. Prince was used to attending our PC(USA) church. The organ would play and everybody would stand up open their hymnals and wait for the organ to finish. We took him to our son’s Orthodox Presbyterian Church. The piano started, people stood up and opened their psalters. When they actually opened their mouths and started to sing out, Prince about jumped out of his skin.
Funerals are pretty unique and I will scorn and liturgically berate my Uncle’s Born Again Christian Pasteur for the funeral service and preaching that he dishonored my Father by… I swear I see him… I will eviscerate him theologically. Most inappropriate pasteur for my Father’s funeral and my Mother thought it was alright because his Brother provided it. she is very naieve and deserves protection from these religous wolves and misleading snakeoil… Kill religion and my Dad would have had the proper funeral.