My dad/abuser is a really confusing person because his main personaltity seems to me borderline overall, but he is also a Dr. Jeckyl/Mr. Hyde in that he switches into an abuser.
I've often wondered if he's got DID and has a predatory alter. Could explain why sometimes it was as if he couldn't remember (or was very good at lying) the damage he'd done.
He could also go from rage to being very tame in short span of time. When tame, it was as if he'd switched into a child and felt a childlike, simple sympathy for me, a child. He was unable to speak much in that state, and his way of apologizing for the earlier rage was to bring a family pet to me, sit there, and then leave.
I never could decide for myself if he was switching or manipulative. It seems like switching since later in life he seemed more PTSD and at war with himself.
Often he seemed to have amnesia for any times he was angry previously. This could be state dependent, but the amnesia seemed clinically significant (if not malingering).
Since my sister and I seem to have DDNOS or DID (although she's in deep denial, despite fugues) I think that it could be both genetic + chronic childhood abuse down generations.
My husband is very accurate in his guessing about people, and he seems to think my Dad has DID. I think some of his alters have PTSD, but not his main personality, which seems more borderline.
Anyway, he'll never go to "real" therapy, my mom won't allow it.
She is the narcissist.
Having a "narc/borderline combo" for parents is the label for hell on earth as a powerless child in their possession.