Rhinestone, I'm sorry you and dh are so stressed out. I don't think you should "just show up" or confront the parents anywhere, however. That could just end up in a dreadful scene and possibly a restraining order - and so, more stress.
If there's any chance of reconciliation with ess and family, I wouldn't go to court either. If you lose, it will also kill any chance of reconciling. But if there's no chance, or if you wouldn't trust a reconciliation, then it might be worth the effort, just to see the gc or say you tried. But you would have to be prepared for ess and esdil to say some cruel things, maybe even untrue. Perhaps dh is afraid of that?
Or maybe he just thinks that, in the end, the parents have the right to make this decision? Whatever, you, obviously, can't force him. Please don't let ess cause tension in your marriage.