He has signed a quit claim deed recently to surrender his interest in the home. His current wife has not seen it or signed it because they are now separated and living in different states.
Great question for a real estate attorney as laws can vary from state to state. Is the quit claim deed recorded? If he has no ownership interest in the home, a creditor should not be able to file a lien against it for something he (not you as an individual or as his spouse) was responsivle for. Also have to wonder if the quit claim was legal based on the fact he is married and didn't have his wife reliquish any ownership interest. Remember, a quit claim deed only transfers whatever ownership the grantor has, if his wife had partial ownership and didn't sign, that ownership would still be in force.
You should consult with an attorney for this question but from my layperson's knowledge of the subject, if the property was quitclaimed to the spouse through a legal separation proceeding &/or stipulated judgement signed by the Court, you may have some recourse to get the judgment against title vacated through a quiet title action. Also, the creditor would have to obtain a judgment against the party before any lien attaches to any title to the home. The judgment is a general lien in whatever county it gets recorded so it will attach to any and all property owned by the judgment debtor (and often times it attaches to property they don't own) therein.