IF he was studied in logic (he obviously isn't), he would respond to you by calling out your post to him as an "Attempted Force of a Negative Proof Fallacy" (because you are attempting to get him to prove a negative regarding an open set, which would be an Argument of Ignorance Fallacy on his part). In other words, you are attempting to force him to commit an Argument of Ignorance Fallacy.
BUT, since he isn't studied in logic, he would likely oblige to your request and attempt to prove their non-existence (thus committing an Argument of Ignorance Fallacy).
His problem is that he has no clue what religion is, nor the logical framework that religion is built upon. He is a fundamentalist of his religions likely due to his lack of understanding about his practicing of those religions.