Mom living with us - driving me mad!

My mother has opted to live with us - basically we’ve all immigrated and she doesn’t have enough money to sustain herself long term and into retirement. We have offered a room in our home and in the long term we will be converting our garage to make a small living area for her. It’s only been a few weeks but having her live with us is triggering me big time. She has always had mental health issues, weight issues, etc, and I’d say her biggest focuses are between how much she hates herself and food. She does nothing physical, if she goes up and down the stairs 5 times a day it’s a lot. We go for walks often and always ask her to join us, she always refuses (even though before moving in she seemed excited about being able to join). Her mobility is now becoming an issue because of this and I have done everything I can to make it easier for her (10 mins walks, knee braces, breaks when she wants it, she can turn around when she’s had enough, etc). She has no friends and makes no attempt to go out and make some, she won’t leave the house unless I am with her. Her car is literally growing moss on it because it’s been used so infrequently. She hates my husband, and I can see that almost everything he does triggers her, so she spends most of her time in her room sulking from a small interaction that really meant nothing - she reads negative intentions from him and gets offended SUPER easily. She can’t take any sort of frank conversations or boundary discussions, so I can’t speak to her about any of this or else it will turn into “Fine, I’ll just move out”, when long term this isn’t a good solution. She is not prepared to face difficult facts about herself and cannot take conversations about how her actions affect me. I’m going mad, and I can see my husband is getting increasingly frustrated with her. Honestly at this point I want to tell her to move out and she must just deal on her own because we can’t keep walking on eggshells around her, it’s exhausting. It doesn’t help that I’ve been at this game (of trying to help her) since I can remember, mothering her since I was a teenager. It’s a big trigger. Not sure what to do at this point… any suggestions would be helpful 😩