My family and I are having a problem with my ESTp brother. He sits around waiting for a chance to call my sister all sorts of vulgar names. If she trips, he'll laugh and call her a dumbass, if she is eating a lot, he'll call her fat, and the list goes on and on. Any attempt to rein him in only leads to him calling us "prudes".
I know he's 13 and that is the time when people are super confused, but he is power-playing with my sister, continuously asserting his "dominance" over her. I really want him to chill out, but I'm not sure how to go about that. I try talking to him about it all, but he just makes a mockery of it, and I can barely get him to listen.