My mother is in desperate need of a stair lift. My mother resides in Michigan and has several medical issues which don't allow much mobility. She lives in a townhouse with a second level and finds it difficult to move from level to level without difficulty or assistance. With a Stairlift she can have some mobility and dignity.
Having limited mobility and living alone has a lot of risks, as Pamstegma mentions above. I would seek information of other options, like a one floor arrangement.
His efforts pointed out the need for absolute precision and competent, qualified contractor installation for a stair lift to be safely used.
In order to have one installed and be safe, I think you'd need someone who does that as a specialty, someone who specializes in assistive device retrofitting. A donated lift might or might not be functional, and given the cost of these I doubt someone is going to donate it, unless you enlisted media help (tv problem solvers, e.g.,) to find a donation source.
You'd still then be faced with proper installation.
Frankly, I wouldn't be comfortable having this done by donation or volunteer work; it's too risky. And these lifts aren't cheap; it's not as if Habitat for Humanity is coming out to paint the porch or something more generic that cold be done by someone with a modicum of skills.
This is a precision installation, too tricky, too challenging, and too risky to have it done for your mother.
What I would consider as an alternate is making the first floor more accessible, assuming it has a bathroom. Give some serious consideration to how the first floor can be rearranged. My aunt turned her dining room into a bedroom. Another friend in her 90's made similar accommodations.
I don't think your mother would lose any dignity by having a sleeping area on the first floor, but what she would gain is safety and the confidence of being able to move about more freely without the risk of falling down the stairs.
There's also the issue of exertion, stress on older limbs and muscles, and of course her older heart. Any of those can complicate the challenges of ascending and descending stairs.
It also wouldn't hurt to consider moving to a one floor townhouse in the same complex.
www.olhsa.org/
If Mom wants something like that, see if there is someplace where she can try one out. If she falls in love it with, then go forward looking to see if one could be donate.