I'm venting here but I am also open to any advice. 

This past week my BiL hung himself. He has a child with my sister. Their relationship was unconventional to say the least and though I was not around for the last several years (to protect my own mental health), I did hear the relationship was very abusive. 

As it stands, my sister (who has BPD) is being blamed and exiled by the rest of the family, particularly my narcissist mother. It is, from what I gathered, an endless barrage of, "I wish I told him to leave you! I know you told him something that made him kill himself!" Whether or not this is true, I feel as if my sister still loved him dearly. I know she is abusive, but that doesn't necessarily diminish her intense love for the few people she keeps in her life. I mean, even I had to leave after years of her using me like a punching bag and stealing from me (though, frankly, the worst was my mother - terrible woman).

My father is the only one speaking with her. He is under the impression that my BiL was hearing voices. That seems to be my sister's and my BiL's closest friend's story. His death did come rather suddenly. No note, he didn't lose any interest in activities, he didn't give anything away, and he never said goodbye.

Either way, I feel so lost. I can't really contact my family. I wont even be allowed to go to the service. My mother doesnt want me in the picture. I texted my sister but it was awkward.. I didn't know what to say to someone I havent spoken to in years. I keep having nightmares of him trying to free himself as he was dying after realizing it was a mistake. I cant stop thinking about my sister finding him and the amount of trauma she will have for the rest of her life. Everyone silences me on my sadness because I apparently dont have a right. I havent been allowed to grieve. Perhaps he wouldn't have died if I had stayed? I could have maybe gotten him the psychiatric help he needed. I was the only person of (semi-) sound mind in that house and I did leave it to fend on its own. I suppose abandoning family paves the way for many unintended consequences. 

I love you, BiL. You were a great friend and a good support while I was still living at home. You will be missed.