I wish you would have gotten more details about the situation with his family. I understand an abusive parent; my own mother was abusive, but his mother, like mine, likely abused ALL her children, although narcissists usually have a golden child and a scapegoat.
He says that his sisters were “mean” which makes some sense - they were abused children, for chrissake, scrapping to survive! Nothing to do with gender, and I promise you, he gave as good as he got in that situation, bc he HAD TO. They all did.