I think I got you beat on the psychotic mother front. If this was my mother, there's no way I'd put up with her shit. My mother came to visit us once when my sons were 12 and 4. The little one would follow her around everywhere wanting to play or just a kind word, but she couldn't be bothered with him. My 12 year old, on the other hand, she absolutely adored and fawned over. I told her I wasn't going to put up with her treating my kids the way she treated me and my brother (older and favored) our entire lives, and if she wasn't going to treat them the same, she could go back home. She WALKED 10 miles to the Amtrack station (I didn't have a car and our town doesn't have cabs) and left. She never spoke to me again. Two years later, she did the same to my brother after he adopted 2 girls after he had already adopted 2 boys. See, she was Korean and had no use for girls whatsoever, and said since he already had an heir and a spare, why'd he bother with girls. One ran into the house excited to see her and she shoved the girl onto her ass. My brother threw her out and it wasn't until 5 years later that she finally started talking to him again, after he apologized for offending her.
When cancer ravaged her body a year after that (8 years after she had cut me off) and a friend of mine called me to let me know she was dying, we flew out to Hawaii to see her before she died. She'd already had a debilitating stroke that left her unable to speak or move and her food and fluids had already been cut off, but I could see in her eyes that if she could throw us out, she would have. We got there on a Tuesday afternoon and she passed in the middle of that night.
She'd given her apartment manager instructions that we were not to be allowed into her apartment, so we had to find a lawyer and get a court order allowing us to stay there while we liquidated all her shit and settled her estate, about 2 weeks. She knew she was dying for a year and forbade anyone from telling us. She gave one of her acquaintances all of her money and signed over her car, and gave her all the shit in the apartment. Which was fine, really, as there wasn't anything we wanted anyway. THAT'S how filled with hate she was. She hated my father my entire life for leaving her when I was young - for well over 30 years. And I mean an ACTIVE hate that consumed her. She died without a friend in the world other than the one she basically paid.
I refuse to live like that. Or die like that. I don't need a lot of friends but if I die with one or two, and my family doesn't despise me, I'll count myself ahead of the game.
So by comparison, my MIL is a joy to be around.