My A dad used to do this kind of stuff to my mom. He'd get all wound up about something and drag her to court and then end up having to pay her legal fees or his child support would increase.
She told me about the last time it happened. He started obsessing about a bank account they'd had when they were married (this was years after the divorce) and took her to court demanding to know who had closed the account. She didn't even bother with her lawyer, just went to the bank and got the signature card showing that he'd been the one to close it. He ended up looking like a complete fool and finally gave up the legal maneuvering after that.
Hopefully yours will wear himself out before too long, like a toddler having a tantrum.