Leave him spinning. It's his mess to clean up and he's going to have to figure out a way to get the child support caught up.
If Child support says that they have no record of payment, then they didn't receive it. I'm sure he'll come up w/the funds because he doesn't want to have to pay interest.
Sit back and watch the show...I have popcorn that I can share w/you. Around and around he goes and where he stops...no body knows!
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.