Tired of sisters boyfriend

Tired of my sisters boyfriend crap. Honestly she didn’t tell him she was taking the baby to an appointment and he was sleeping... Anyways I asked if she wanted me to go and she said no.. He’s mad because of that I am just annoyed because he was like you always take her side. Lol I am tired of this because I am paying the bills and honestly he can gtfo with this bull. Not even that he said oh my mother told me she would do something that that. His mother who by the way doesn’t do shit to help us with a place to stay or even let him or my sister and the baby live with her. Gtfo lol. Okay, I am good now.