Dealing with a negative family member…or a person who just likes to put you down

Imagine marrying into a family like that, they constantly put down everybody, including people that help them. My ex father-in-law could not figure out why I would not work on his vehicles, he would ***** and complained to everybody that I would not help him out. I did once but then I heard what he was saying behind my back and I never did it again. His daughter was the same way and after 19 years I sent her on her way. All people are doing bye putting you down is trying to build themselves up and it’s truly pathetic.
If I were you I would block your brother forget about it.
Good luck