I cannot suggest anything to help, but families are hard work, I don't get on with FIL, he treats his wife like a servant, he is a lazy bully. My partner knows I don't get on with him, so he doesn't drag me along to see them too often.
However we had to go the other Christmas as, FIL, got told he has Kidney failure and heart failure, the doctors said if he takes care of himself he could have 2 years left, however FIL isn't the type to care for himself, drinks too much, eats too much, doesn't exercise much. So my partner thought, his dad might not be around for much longer.
It was a massive disaster, mainly down for FIL been a pain. He had pain in his legs, due to not elevating his legs, when he finally decided to, his was in too much pain. He had been prescribed some tablets, but they were running out, the doctor had told Mil, they wanted him to try without the tablets, so basically when they ran out that was it.
But he wouldn't be told, it was Mil fault the tablets had run out and that's why he was in pain because he didn't have the tablets. This was Xmas eve.
All night, he was moaning and complaining. I must have passed out from exhaustion at some point, only for the Dam cat to start screeching the house down at 3 am.
Christmas morning, he demand he needed the tablets. So had to go to the hospital to pick them up, they had to see him, as course of tablets were not on repeat. My partner and mum took him to hospital, but got told it could be a hour or more wait, so they returned home, so my son and his neice could open there presents. FIL got seen but was grumpy they hadn't sat around waiting for him. He wasn't bothered he ended up making Christmas miserable, as the turkey dinner was cooked for 6 as he was at the hospital for 12. But he had a face on, that he didn't have mustard for his pork pie. (when we had dinner)
He went all day without eating, because he didn't get turkey at lunch time, but for tea. Nightmare, but we have decided, we cannot go through that again, even his daughter who lives nearby doesn't vist much, because how he behaved that Christmas. We suggested that Mil could do with home help, as she was getting stressed and hid away from him in the kitchen for a hour or more. But she wouldn't except help.