My sympathies, and sorrow for your loss.
If you could find an (inexpensive) attorney, they would be able to do all of this for you. Plus, they might know of some other agencies you should/need to contact as well.
You will need several original copies of the death certificate - but I can’t tell you how many as that depends on who will need them. However, I believe everyone who needs one will want an original, and not a photocopy.
Regarding wheel chair and other equipment - I know Goodwill takes them, but you might want to contact a hospice and see if they need anything - or have suggestions about some other place that could use the free donation.
You might also want to check to see if there are any insurance policies you might not even know about - often bank/credit cards offer a “free” life insurance with their cards - usually not a lot, but even if it is $1000 or so, it could help pay for the attorney.
It is a lot to go through right now, but I am sure there are many things you might forget or not know you need to do - let your car insurance company know, inform mortgage company, change utility bills to your name, inform the DMV and lots of other “little things” that will pop up That is why I would strongly suggest at least contacting some legal aid organization in your area and ask if there is someone who might have a checklist of sorts, or someone who could speak with you and go over the basics.
Just a simple thing like a Last Will - if there are any relatives who might be hovering around - will make things easier, but if not, there are basic laws protecting the surviving spouse.
Most people also suggest not doing anything drastic for at least a year - not suddenly selling the house, or selling the car, or moving to some other location, or whatever - that is a common first impulse, but one should wait for that first year before making any kind of major life changes after the death of a spouse.