Narcissistic Father

It’s been a while since I’ve written here. I guess I’ve been feeling sad lately that my family has broken down. My parents’ marriage is like essentially done. They still live together but haven’t spoken in years. My father is a narcissist who’s been financially abusive to my mom throughout their marriage. I supported my mom to stand up for herself and stop taking the abuse and no surprise, the marriage was only surviving because she was absorbing all the abuse. Once she stopped, the marriage broke down. My father lost his business, cars, land and most wealth that he and my mom had built over 40 years of marriage within 5 years. I’m happy that my mom is out of that situation. I have no regrets about helping her. But it’s been really difficult witnessing my father’s life crumble. I keep waiting for him to dust himself and pick himself up but so far, nothing. He’s barely taking care of himself. Doesn’t eat well, doesn’t clean his living space, spends the little he has left on medications for real & imagined illnesses. I think he does that on purpose to sort of guilt us into taking care of him again but he’s well capable of doing that himself. And when we used to do that he was very abusive to us.
I kind of didn’t realize that their marriage ending also meant that our family was ending too. They don’t speak so we can’t go anywhere as a family, we don’t eat together, we don’t do holiday stuff anymore. Like we’re in the same house eating alone in our rooms coz being in the same space is triangulation hell. I think that’s the part that has caught me off guard. I hoped that my dad would change & salvage the family but it looks like he’s just going to let it rot. That’s disappointing. I feel the damage that has been done now is irreversible but even more sad is because we don’t have too many years left together. I feel he has robbed us of our happiness, and for what? Ego and control.
Obviously I can’t fix their marriage or their lives. I just don’t know how to detach myself from their self negating decisions.