how do I tell the difference between my friend potentially being a nazi and just really messed up dark humor?

im gonna be honest, stuff's been wild recently, including the potential of one of my friends being a nazi, I need help figuring out if he is one. okay so basically he keeps making hitler praising jokes, and he even did the nazi salute. he said how hitler did one thing right: killing the jewish, and I dont know if hes joking or outing himself, i dont want to associate myself with a nazi!