With reference to my father, I have often wondered if it was more like a "character" flaw.
I do think that like someone said, it is some sort of combination of an inherent tendency combined with life circumstances.
For a certain period of time, I had much sympathy for him. Today, I have some sympathy for him, but much less so. I have disengaged.
The reason why, is I feel that when we become adults and our behavior causes problems with those around us, particularly close family members, it is up to us to get help.
It is sad and unfortunate that we might have suffered difficulties in our childhood that contributed to the problem, but that is not an excuse to go on causing difficulties and problems for others and this goes double for close family members.
In the case of my father, he was abusive to my mother and my self. He had horrible difficulties holding down a job. So, he opened up his own business, but never really worked more than part time and he made very little money. He saw himself as a big businessman and it was anything but this.
AND he had perfect health, while my mother and I did NOT. I made great grades in school and worked pt after school. My mother made more money than dad, but he never gave her any credit for this. She took care of me and the house...while suffering horrible abuses from him. Then she got sick and died at age 49.
Then, my father refused to pay any money to give her a proper burial, with the money that she left him (long story), but it ended up being a lot. When I got married, he didn't want much to do with me, and when I had kids, he totally cut me off. At one point when I tried to reconcile with him, he was terrified that I would expect him to buy gifts for his grandchildren. He never knew his grandchildren and this is the way he wanted it. It is sad and weird.
My biggest issue with it all, is that with all the losses, it is hard to believe that it never dawned on this person that perhaps they should get some psychological help. Even at his age, he still believes all his problems are someone else's fault...never his own. Never looks in the mirror.
A small part of the problem is that others (cousins, etc) enable him a bit. I know his mother certainly did. We actually talked about it. But she said that she learned to give in...it was easier. I just wish she didn't always do it...consistently giving in like this had to make his personality disorder more ingrained. But she was a single mother and a bit lonely and frightened. It had to be sad and painful for her.
I agree..disengage. I would pick and chose battles. Never let them abuse you in any shape or form. On occasion, tell it like it is...although they are not likely to hear you. Perhaps in time, they will; especially if they hear it coming from your mouth and a second source. If it is a young adult we are talking about and you have the resources, offer to pay for counseling or find a low cost clinic and hand them the phone number. If they are in a tirade, get away. If they are talking with- you on the phone, hang up. Texting...cancel texting for awhile and put it back later with-o their knowledge.