During the lifetime you can pray for anybody, for whatever you please. That verse applies only to a state after death. After your idolater friend is dead, then do not seek forgiveness of Allah for such a man who died as idolater. That is what is said. But to try to defeat the purpose and find a healer, this is what you want. So for that, instead of asking me a question, refer to a book, Kitab-ul-Hair. That will provide you with something.