My ex-hubby and I were getting married after my son was born, and when my son was born he signed the birth certificate knowing he wasn't his son. (My son's bio didn't, and doesn't want anything to do with him at this time) We ended up getting divorced and it was final the day after my son's first birthday. He was granted no visitation and has to pay child support. The final judgement on the divorce was abandonment. That was in 2000 and now, after 8 years, he hasn't paid child support in 6 years, almost 18 thousand behind and hasn't seen my son since the divorce. He hasn't contacted me up until recently. We have DNA results showing he's not the bio and we are trying to find a way to drop his rights and child support. He is trying to get a better job but there is a hold on his license to where he can't get his CDL and that's holding him back from getting his raise and the other job he's trying to get. He and I agree that he shouldn't have to pay this and are looking to drop the situation. I am married again, however, I do NOT want my husband to adopt my son. We have a daughter together, but that's another situation that has nothing to do with this one. Is there any way to drop this with my ex-hubby so he can get his life straightened out and be able to take his newest ex to court to get child support and visitation established? Also, they have been withholding his taxes for 4 years and he hasn't gotten any of it, nor have I, can they do that and not distribute it to either of us? Just hold it because of child support and not actually give it to me or back to him?
Thanks

Simple answer-NO.
Modifications of retroactive CS payments are prohibited.
You can relieve him for future payments only.But I doubt of that the Court will disestablish him as a parent if there is no a biofather or a new spouse who is willling to adopt stepping on the scene. I do not know if he is forced to pay by CSA or not.