I don't know how to handle this

So, I'm in a great relationship & I love my so's family dearly & his mom (my mil) is such a great person & I love her so much , but.... I'm having problems with her mother. She is a good person & grandmother sometimes but she has Alzheimer's & I'm trying my very best not fuck up anything with her.

Anyway, let me give you some scenarios. She is accusing me of everything. She thought that I was "going against her" when her grandson (my little bil) not to talk back to her. Because you know, that's what good manners is. She thought that I stole her car many times, which I didn't. I asked her a few times if i could borrow the car & she said yes but because she has Alzheimer's she forgot I even asked her. She thought that I said she couldn't have dinner, WHICH I said that she couldn't have 2 portions of dinner when no one else ate. She had a full plate of food & then an hour later proceeded to eat my portion of dinner! I told her that everyone needs to eat & she took it as she isn't allowed to eat! She also calls me for EVERYTHING. See my so is her favorite grandchild so she treats me terribly. For example, my so left a little mess in the bathroom & didn't clean it up, so SHE CALLED ME TO CLEAN IT UP! Like what??! I don't understand! She does this with everything! & just now(!!!!) She thought I said that she wasn't allowed to come downstairs! I never said that! What I said was "let me see what we have downstairs for dinner" so I got yelled at (a little) by my mil. I told my mil the truth & she brushed it off (which is fine, that's how she is)

I don't know what to do, I'm on the verge of crying. I don't want to complain because that will just stir the pot.

& if you read that whole thing, thank you. 😔

I just needed to let it out...