there are lots of programs in our area for seniors / low income households. I'm not sure what she would qualify for living with you, but it doesn't hurt to check into all the programs available, now and if she could potentially move out. An older friend of mine just moved into a subsidized senior living center after being on a wait list for 8 years, so the time to get on waiting list is now. We live in an urban area with several senior clubs and they all have resources for help. Most counties or cities have some kind of aging department with social service workers knowledgeable about programs. One of our senior centers has a roommate match program for seniors, where they do the screening and background checks.
Other programs in our state / local area include - snap (food stamps), free lunches at the senior centers, free activities, discount public transportation passes, wholesale produce at the farmer's markets, almost free senior bus service, low income utility programs, low cost internet, free phone service, free uber rides for seniors, free college classes and more. The library has all sorts of free classes and event passes, plus the usual books, streaming services, ebooks, music, etc. (some of these have been suspended during the pandemic.)
i actually sit around and think about this, what would i do if i only had ss to live on, as an interesting math problem. It would cost around $800 here to rent a room golden girls style, but that would be in a nice house on a bus route. (if there wasn't any subsidized housing available). But after rent one could probably live a fairly normal middle class life with all the programs available for help with just the programs and ss. It would probably mean not owning a car, but in the cities here many people don't use their cars much anyway. (one of our adult kids lives in a walkable area and has a car but was happy it started the other day from having it sit so long without needing to drive anywhere.) it is a plus your mom has free medical care. In some cities here college students get free bus passes and seniors in our state can enroll in college classes for free.
For extra income she could probably pick up a few hundred extra dollars with ideas in reddit's beermoney forum. Some people there make over $1k a month. And maybe she could try some gig work like dog walking or pet sitting for extra money.
We've had thread on this before and one solution was to buy the parent a mobile home in an affordable area in a 55+ park. We had retired friends do this in a vacation area and it seemed to work out well for them. They had pretty low overhead. Or maybe if you don't mind her living with you, you could convert a garage or get a backyard cottage for her to live in so your each have your own space. I am not sure why so many posters here are acting like having your mom living with you is so awful. Housing is super expensive in our area and multi-generational households are pretty common. A number of homes in our area have mother-in-law units added on, either parents, adult kids or for extra income. Laws were added last year to encourage people to build more adus to help with the housing shortage.
^^^ all of this!!!