First off, your post brought tears to my eyes. I've read and participated in many posts here and this is a first for me. I want to send you virtual hugs, off the bat.

I recently purchased a book called, "It Didn't Start with You", by Mark Wolynn. You might be interested in it because it talks about generational trauma and how it affects future generations. Reading your story made me think of it. I didn't pick up on the narcissism, either.

Your parents seem to be struggling with unresolved trauma. As young children, they were forced to mediate traumatic scenarios beyond their means. They didn't have the resources to work with so all they could do was maintain that peace. How they handled your brother was very much in the same way -- limited. They likely need individual therapy to address this before being able to support you in the way you're needing it. Do you think they'll be willing to? That's my opinion, anyway.

One relief for sure is you're living in a supportive environment now. I'm not sure if it's a good idea to tap into professional support (for lack of a better explanation) with the parent you're living with, though. Despite her professional experience, she's too connected to you to be able to be objective. Saying your parents are "narcissistic" is an example of that. She cares about you and I worry that her professional advice is a bit clouded now. Again, my opinion.

Would it help if you saw a therapist with your parents? Is it possible to visit with them, apart from your brother? This may be a starting ground and an opportunity to hear what they have to say.

Your brother sounds unstable so I don't think it's in your best interest.. physically, mentally, or emotionally to be near him. Yes, he's been abusive towards you. There's a zero difference between throwing a pot "at your head" vs "near your head". They both instill fear and pain to the victim. I suspect he has some mental health or personality disorder of some kind, he'll need to address for himself. It was not your fault.

With regards to your parents asking your brother what "you did" when he was in escalation mode.. I suspect that was a strategy they adopted to buy his interest. If he felt they were siding with him, the risk decreases in the moment. "Don't piss off the unstable" was possibly their mentality. If he doesn't want to attend therapy now, it's possible he didn't want to then, either. The conversation you overheard made me think they tried to reason with him with respect to you. No one can make him care, though. The problem is his.. and perhaps he, too, is a victim of generational trauma.

I hope all the best for you and am sorry for your struggles.