Am I wrong? Sister mad that her BF broke up with her cause of me.

This ahole cheated on my little sister. They broke up and then got back together. I never got into their business about the cheating. But then 3 months later, she told me he pushed her out of anger over an argument. She fell to her butt and was scared. Then on another occasion he grabbed her by the arm really hard like he wanted to push her but didn't. Ever since the abuse I have been mean to him and confronted him about it several times. I even brought up the cheating to his face once when they argued in front of everyone at a friend's event. Then on Father's Day this week (after my dad left and all the siblings were hanging out) he got really drunk and started teasing me. I dont know if it was my preggo symptoms or what. But he already annoyed me to begin with. I said to him "at least im not a shovensit". He got mad and started defending himself. I just laughed and said okay. That night he broke up with my sister because he said he couldn't stand her family. I'm glad that he can no longer abuse her because I don't believe she tells me everything. But at the same time my sis is heart broken and won't talk to me. She's only 24 and I'm 6 years older. Was I overreacting this whole time? Please give me some advice. How can I repair my relationship with someone who won't talk to me.