If it is true that he has some form of magical protection we'll need to find that out and figure out how to undo it.

If he has been possessed by some entity, we'll need to find out who or what it is, and figure out how to deal with it appropriately.

Either way, finding the man seems to me the first order of business, and from there we can perhaps learn a little more about the situation and what we're up against. Wouldn't you agree?