<human>: Can you condense the text into a few key points?

I was adopted, and my adoptive parents always allowed for a relationship with my bio-family, minus the mother who was court ordered not to be around me considering the amount of abuse that went on there.  
Which includes my grandparents on both sides.
Now, for some background here. My biological brother has been, odd, for many many years growing up. He'd copy everything I did, even including my mental disorders.
Thankfully, he stayed with the biological father and I Was given up because my bio-father didn't believe I was his kid..

Basically my brother was fucked up. I'd bring this up with family, my adoptive parents and biological grandmother, and they'd just say "he loves you, etc. etc."
Now, about eight years ago, after molesting me on and off for years, he raped me. My grandmother REFUSES to believe ANY of this happened, and gives me "updates" on my brother, inducing a panic attack two weeks ago being told that he had had a child with his girlfriend.  
I've tried to tell her off, I've tried to tell her I don't care about the brother anymore, I don't know of any solution other than just cutting ties with her and my grandfather, if they won't listen.

Am I overlooking some other answer here?

And yes, I have been in therapy for this, I'm doing MUCH better than I was years ago.
<bot>: Brother sexually abused me, grandmother won't listen and wants me to talk to him still, wondering if I should just cut ties with my entire biological family.