My mother wasn't a perpetrator, exactly, but I think her issues contributed to the abuse from my brother. I think she had "dependent personality disorder". She was so focused on how to get others to take care of her that perhaps she didn't consciously think she "could" do anything to stop my brother's abuse, when not in total denial that he was regularly abusive. (Plus she was an emotional black hole; maybe what some folks call a vampire but in a passive way.)
She'd emotionally put him in the category of someone who needed help like her, and not me (maybe because I dissociated all my issues pretty effectively and went off and got good grades to escape?) She'd admit that my brother was abusive and dangerous for a couple of days after each episode, then, if there was a break, he was "getting better" and nothing that had happened was as bad as (fill in the blank with whatever horrible thing you want). However after I left that house, she continued to try to get me to interact with my brother, so I felt forced to regard her as unsafe and didn't interact with her much.
She kept doing less and less for herself and died in a nursing home, she wanted more and more done for her but she wouldn't even get up for the last 2 years and I think it destroyed her heart. I feel pretty intense guilt pretty often over not somehow "helping" her; that's the emotional side that she encouraged and was a big part of possible connection to her, then I still have this pretty strong analytical, "she wasn't safe", side, that was a survival thing to cut off most communication. Those sides don't meet too well. The concept of "she should have kept me safe" is emotionally blank for me though mentally I think there's something there. I've been reading on dissociation.
@
Hashi, I guess I never totally cut off communication with her, but I did limit it a lot and maybe got somewhat better at taking care of myself when contacting her, over those last few years. I think one thing her death has changed is that I no longer think so much that if I just say the right thing to her, she'd become safe, everything would magically improve... some boundaries are more clear to me now, as it's more clear that she just got worse and worse no matter what I did, and she had her own internal feedback loop. One thing that I think about is that our time is limited, so to try to heal ourselves we can't wait forever.