So the elders are basically saying that you and your mom can't associate either? That's bull crap. You're out. She's out. Your dad and mom are a package deal and the elders can't stop them from associating with each other. If he goes someplace with your mom, and you are going there with your mom, the elders are putting their noses where it doesn't belong. All he has to say is that he is not speaking with you and that would satisfy their idiotic rules. There is NOTHING that says that he has to become a recluse in order to avoid associating with you, when you and your mom have every right to do so.
Your non-JW relatives have put your dad on notice that if he shuns you, then they will shun him.
Your dad is being painted into a corner by the elders. It's getting smaller and smaller, and pretty soon he's going to have to choose to be DFd by the JWs or be DFd by family. It all depends on whose love means more to him. Surely he is learning that JW Love™ cannot replace the love of your family.