Omg wow please know I understand. She sounds like my sister. I say dealing with her is like walking through a landmine field. If I don't ALWAYS agree with her, or dare try to stay away from any topic, she explodes and attacks me. I have tried to set boundaries with her in what sounded like a similar way as you, where I said, I'm not comfortable discussing abc subject with you because I don't agree with your view and that's never ok with you so let's not discuss. She shrieks "only a crazy person wouldn't agree with that" etc

I just went from LC to NC ... again. nMom and nSis really hate when I won't be part of their sick triangle. Sis is furious, playing rescuer to mom who's acting hurt I'm not talking to her... she attacks me saying our father doesn't like me. Sis is very competitive with our dad (divorced from mom since I was 6). Well. I got out my phone and recorded her ranting this time. She said my brother and sil also thought dad doesn't like me, all on the recording. I emailed it to dad, brother and sil. Dad called and we had a nice talk. Today I realized sis blocked me on Facebook. Possible fallout? I hope so.

I post this because I wonder if anyone has ever witnessed how nasty your sis gets. Oh, mine's an alcoholic too, same as mom.