I'm unsure you can do anything about the school situation if its not in your decree
He can't do anything about child support he agreed till end of school year. He could modify - not sure he would do that. Hold him in contempt if he stops payment.
I think best is to go see your atty and discuss if its worth it. It is possible if he has lost income he could end up with a modification of support in his favor.
I gave up my rights to his freaking pension and he's still not grateful for what I saved him
Because he never felt you had any right to it in the first place. For those going through divorce do NOT give up what you are entitled to, you earned it.