He does not have a job, friends or much of a life at all - he says this in his own words. He stays in his room all day (at my parent's house, who enable him, but that is a different story) and mostly just complains about how miserable he is.
This sounds like my brother when he was younger, and your parents sound like mine, at least until my brother turned 26.
uBPD brother became violent with my mom and that was a catalyst to get him out of the house with a lot of financial help, including paying off his debts and buying him a house. Apparently having BPD was lucrative in my family.
I agree with you that only your brother can change himself -- he is ultimately accountable for himself, no matter how much he avoids this responsibility. However, like you imply, your parents have no small role to play here. You might also have one, too, though it might not seem clear.
I was the weakest person in the family system, but I see now that changing my script did have an impact, although I may be overstating my contribution since other factors were also in play.
After one holiday visit that ended in violence, I stopped visiting my family even though I lived 30 min away. I finally had an epiphany that my childhood home wasn't safe, probably never would be, and the only person who seemed to care was me. So I said I wasn't coming over for Christmas and it rocked my parents.
I'm still not sure how being beaten was ok but saying no to it wasn't.
This choice create a violence vacuum for my brother who, having no one to beat up, attacked my mom. I guess it was ok to be violent toward me but not her, because suddenly my parents were motivated to get uBPD brother out of the house. When I chose to protect myself it was met with outrage but hitting a mother mobilized the Great Relocation of uBPD to an apartment.
Like other covertly narcissistic families, the violence was kept quiet and alluded to but never discussed, and managed internally.
Decades later, I read Harriet Lerner's Dance with Anger among other books she has written about family systems and triangulation, and realized that I had been functioning in a role designed to stabilize unhealthy family patterns. The problem is that the refusal to participate in a dysfunctional dynamic truly can cast you out of the family in more ways than one.
It's interesting to hear that your family seemed to mobilize when your brother became violent -- towards himself, if only the threat of it (suicidal ideation).
My parents used to be very protective of my brother, and then I stopped asking questions. If they brought him up I listened but usually changed the topic. Oddly, this led to them discussing his issues much more openly and they began expressing their anxieties and fears about him. The less I say, the more they share.
Like you, I don't see things changing. They are too enmeshed and this is probably as good as it will get. Despite my brother refusing to visit my mom in the hospital and dysregulating in dramatic ways over the death of family members and pets, my parents made my brother health care power of attorney and executor of their will. My mom has expressed worry about having uBPD brother be in charge of her if my dad goes first, and I simply listen. There is no point in stating the obvious because
that simply reprises my old role. She is an adult child looking to be rescued and the best way to empower her is to not participate in the game.
It's very sad, and I do feel grief although less so as I process things. It has made me think very deeply about what it means to be a family and how to put my own in perspective. Sometimes I think the most impactful thing I can do in my family is simply be a mirror and hope they decide to take a look.