Soon To Be Ex-husband Stopped Paying On Loan And Ceased Communication. Do I Have Any Legal Standing?

I (27F) and my husband (28M) separated in March and plan to divorce this coming March (we live in NC where separations must be at least a year). It SHOULD be an easy and amicable split, as we have no children, no house, and no combined assets.

BUT my ex has a private student loan from Sallie Mae, of which my stepdad co-signed. The amount is ~$36,000. Sallie Mae has a plan where if my ex were to make 12 on-time payments on his loan, the co-signer (my stepdad) would be dropped from the loan entirely. This was the whole plan and what my ex had agreed to do. But he has stopped paying the monthly payments, and has now ceased communication with myself and my parents. He will not return texts, calls or voicemails. He also moved addresses and we have no idea where to even find him. My stepdad acknowledges that he made a bad decision in co-signing in the first place, but what’s done is done.

He now has to choose between stepping up and making the ~$550 monthly payment, or taking a MASSIVE hit on his credit. My mom had planned to retire this coming year, and they don’t have a ton of extra money to begin with, so this has been incredibly stressful for all of us.

My question is, is there any legal standing when it comes to this? Is it something I could address with a divorce attorney or something my parents could take to small claims court? Or is legality completely out of the question since my stepdad chose to co-sign of his own accord?