Realistically speaking, he can't prevail on adverse possession. Were he to bring a lawsuit, he would face the issue both that he's making a claim involving the same land against the same owners, as in his prior suit, and also that he reasonably should have included any alternative claims or theories in his original lawsuit.

That doesn't necessarily mean he could not successfully get a court order to stop any action by you that would damage the portion of his home that extends onto your land.

I suggest discussing your rights and possible next steps with the lawyer who helped you in the adverse possession case, as that lawyer will know the specific issues decided by the court, the laws of your state and the full facts of the case, and should be able to explain any residual rights your neighbor continues to possess despite his loss in court.