please tell me who is in the wrong?

I apologize in advance, this is probably going to be a long post and hard to follow. Ever since we were kids, my older brother has been verbally, physically, and emotionally abusive towards me. He was never sexually abusive but he had said sexually inappropriate things to me when he was under the influence like asking me if I wanted to see his penis. His behavior was so bad and he was expelled from school and was ordered by the court to go into foster care for two years in hopes of shaping him up. Needless to say, we are both now in our 20s and his behavior has continued. He is prone to outbursts and is an alcoholic and drug addict who refuses to seek help. Now that I'm in college and have taken a few psychology courses I can see that he has some antisocial behavior tendencies as he does not ever seem to feel remorse for his actions and he has also been diagnosed bipolar. I don't really keep in contact with him if I can avoid it because after a few weeks of everything going okay,  he always does something terrible that will make me never want to speak to him again. For example, a few weeks ago when we were at my parents house, my dog was barking at him because she does not like him and he lunged at her attempting to kick her and she ran away crying. So since that happened I am not speaking with him again. Anyway, last night he got arrested which I heard about through the grapevine. I called my mom to ask her about it and what happened (she knows of the things my brother has done to me and that I do not wish to have a relationship with him) and she refused to tell me because "if you do not want to hear the good things about him you do not need to hear about the bad things." I was in shock and dumbfounded that she would assume I would want to hear anything good about my abuser. True, I do not like to talk about him EVER but I think I have a right to know what crime he committed. She is always telling me that I need to forgive my brother and allow him back into my life. But truth be told I do not consider him my brother, but my abuser and I have no wish to allow a toxic person back into my life and I can't believe that my mother has the nerve to try to force me to do so. Keep in mind he also has abused my mother in the past and now she enables him. I think she is suffering from Stockholm syndrome and is also experiencing guilt over sending him to foster care when he was a teenager. I tried to tell her this and she completely denied this. I then told her that I feel I cannot have a close relationship with her if she essentially cannot accept that I am a victim at the hands of my brother and respect my wishes to not have him in my life. Is this wrong of me? I feel that she is trying to put the blame on me and make me feel as though I am in the wrong as she is always protecting my brother. She even denied that he did anything wrong when he got arrested, she said he was being instigated. Please tell me if I'm being unreasonable in my wishes and actions.