Long story short I’ve never liked my bil but I’ve tolerated him because my sister married him and he is her kids dad. The final straw was him body slamming one of their dogs and calling shelters to get rid of her. She constantly digs at her back until there are sore’s because they don’t treat any of their pets for fleas. While one of the kids were jumping on the couch by her she snapped at them. She has never been aggressive and usually sleeps with one of the kids or my 70 year old grandma. After doing that in front of my grandma (she was very upset and still is) he has kept her in a cage for days and won’t let anyone see her. I don’t want to defend the dog for snapping but IMO The kid and dog aren’t at fault; The adult/owner is for being irresponsible. The kids too young to fully understand and the dog is a dog. Throughout their relationship he has gotten and ‘rehomed’ at least 12+ pets for various reasons. He never asks my sister before doing any of this and ignores any objections or concerns she has. He usually picks one to particularly hate and be mean to (usually the smallest). He’s literally thrown a small dog in a crate, left cats behind when they moved and gotten a new pet within 24 hours of getting rid of another one. I can’t tolerate a man that can so freely abuse animals and won’t admit when he’s made a mistake. I’m honestly a bit scared of him and the possibility of him doing something like that to her or the kids.