Distressed, I agree with Elana that it sounds like you are the only sane one. I think that you did a good job with setting a boundary when your Uncle told you to SHUT UP and you calmly told him that you didn't appreciate him saying that to you. That is a good way to take care of yourself, by saying that to someone who is verbally attacking you.

Your family does sound quite dysfunctional. That doesn't seem like appropriate problem solving to send you --a capable adult to their room. That sounds strange. Especially after your mom asked you for your support. I think if you were asked to read the papers by your mom then you have the right to ask questions about the terminology that he uses.

I'm sorry the situation ended as it did, but I think you did a good job handling yourself. Maybe your mom should look into getting a lawyer.