I can speak from experience. Recently left everything because the abuse moved towards my eldest daughter after standing up for myself and refusing to tolerate the behavior. I witnessed my older brother being abused by my father growing up. All while protraying to outsiders that we were a normal, happy, family. I refuse to blame others for my issues and mistakes but, logically, it makes sense now why I put up with it for so long. That was "normal" for most of my life. I didn't recognize any major issues until I was too far in. Once I snapped to what was going on, I felt like it was my job to manage it and deescelate situations since I was the one who made the decision to be there in the first place. I watched my mother manage it for so long. It didn't seem so crazy at the time. I'm not sure how an outsider can help, other than listening when someone is speaking out and asking for help. When family/friends say they don't want to get involved/pick sides, they are picking the wrong side.