Another suggestion - (maybe I said this already) is to go to court and get a limit put on the  number of semester DH has to pay child support.   Your cout order will over ride OR state.  From what I have read, you are not in the same state as daughter/x.

If there is a court order with an end date, the support will stop.   Period.

And if DH gets it done in the state he lives in, then if the daughter/x want to challenge it, they would need to do it in HIS state or request a change in venue.

I think any  judge would be somewhat sympathic to what could be a lifelong bleed on the bank account.