Hey OP! I’m not the best person to help, but I had a cat that lived 21 years and by her final 3 years, she didn’t know where the bathroom was supposed to be anymore. Since we had a fully carpeted home, we bought female dog diapers (an example and they worked super well. She wasn’t soiled anymore with pee (since they absorb a lot of moisture), and changing her was much simpler than cleaning carpet. So maybe you could give this a try, in case your cat won’t mind them that much.
Just a question: does she crawl around? Is she able to use her litter box? I’ve heard of people using shallow cookie sheets as litter boxes because their CH cats couldn’t get into the more deeper ones. It sounds messy but I guess it’s also a possible solution.
In anyway, thank you so much for helping and caring for your special needs girl :) I’d be glad to help you brainstorm any possible solution.
My cat has CH, not like a bad case of it though, she and our other cat as well as our fosters love this tree: Go Pet Club 62-Inch Cat Tree
The hammock is her favorite spot and the ladder helped the kittens get into when they wanted. It is a far jump down and you can always leave off the top piece too.