Hannah, I know you are trying to help her, don't get me wrong... this is just something very fresh for me about human rights, and has been tested literally for us in the last few weeks. Tbh, I'm surprised there are already cameras in the places you go to.
Would she be safer in a home? I know it isn't for everyone.... but we have had some people move into a home, as they weren't safe on their own. Or could you get someone in at mealtimes, to check she eats, takes medication etc?
There will be help, financially, if she needs it.