I have a brother-in-law that lives in Connecticut, and for Christmas he gave everyone here in Oregon Texas Roadhouse gift cards. I guess he thought those places were all over the place.
Well, they aren’t.
What I am looking for is a restaurant gift card for him that is unique to Guam as a gag gift. 
Anybody?
I can’t help you about Guam.
But these folks are a local Greater Miami chain of sports bars. Their food and drink is actually not bad by any reasonable sports bar standard. They sell gift cards your BIL would “enjoy” not being able to use. 
I know of your personal connection to Guam, but I think to penetrate your BIL’s general cluelessness you really need a small chain local to Portland or at most the PNW. About which region I know just about zippo. Beyond Dick’s Drive-in burgers in Seattle, that is. Who, sadly, don’t seem to sell gift cards. But you could send a t-shirt. 
It looks like Texas Roadhouse does have locations in Oregon, but none close to Portland.
@Czarcasm needs to get his BIL a gift card to McMenamin’s, a chain only located in OR and WA.
McMenamin’s is a good choice. Maybe Burgerville.
Bucc-ees
If McMenamins sells anything online, that utterly defeats the purpose. The OP needs something the recipient can use only by visiting Greater Portland, or Oregon, or maybe the PNW.
It seems McMenamins sells everything they make online. So a total failure for tweaking OP’s BIL’s nose.
Or Guam.
Yeah, I know it’s not likely such a thing exists, but anything less is probably too subtle.
Hey, you can save a bit of cash. Just get the physical card. No need to add cash..if you don’t expect them to use it ever.
Why limit yourself to North America?
There is one close to Seattle, a couple of hours away..,on a military base. The next closest one is in Kennewick, Washington. If you look up how long it takes to travel from Portland to Kennewick, well, that isn’t going to happen. Also, as others have pointed out, just about any gift card from the Portland area also sells merchandise that can be shipped.
Getting a card, empty or not, from Guam is still the problem. I picked Guam because I am originally from there.
Ahh..I see.
Have you not any contacts or family there?
Not any more.
I just spent about 45 minutes “flying” around the island in Google Maps. What an interesting hodgepodge of a place.
Sadly when it came to restaurants I found national franchises & Mom’n’Pops, with little in between who’re big enough to have a website and gift cards, but small enough not to have an outlet off-island, and especially not in the US Northeast.
There was one promising outfit who clearly have MBA dreams of growing their 4-store empire on Guam into a US national franchise powerhouse. Or at least being bought out by somebody like that. But they’re not quite big enough yet to mess with gift cards. Missed it by that much.
Maybe just wrap up the unused Texas Roadhouse gift cards and give them back to him like you just bought them. Of course there’s a chance he doesn’t put it together, but either way, you’re not shelling out your own money.
Otherwise, I’d think a local mom n pop place would be your best bet. I’d imagine plenty of them don’t have much of an online presence beyond social media and certainly aren’t selling anything over the internet.
If you really want to rub it in, what about going beyond restaurants? Maybe a corner grocery store or the hole in the wall hobby shop?
Maybe a local bar instead of a restaurant?
Ah, but their gift card page states “Gift cards cannot be used for online purchases; however they can be used to place a phone order by calling (503) 492-5499.” But I guess the OP’s BIL could place an old fashioned order over the phone if he really wanted to use the gift card.
Some gift cards from corporate restaurants will be accepted at a variety of their other restaurants. For instance, if you get a a Chili’s gift card, it can also be used at Macaroni Grill and some others. The same is probably true for the Roadhouse GC, but, unfortunately, I don’t think it will help you. Roadhouse has a couple of other restaurant brands, but they aren’t in Portland.
For your BIL, perhaps get a GC to your favorite local place in Portland that only has that one location. He can use it the next time he comes to visit.
Panda Express.
I bet Guam don’t have those!
Oh wait. That’s not the need. You need where your gift recipient lives to not have a certain restaurant.
Hmmm.
You’d lose that bet. https://www.pandaexpress.com/locations/gu/hagatna/2317