Is your friend scared to go by himself ? Like Diakoneo said, it seems that certain people are more susceptible to this kind of thing. I have a good (Christian) friend who is convinced there is an older home in his neighborhood that is haunted. Strange things supposedly happen- mysterious appearances of people, furniture moving, so on and so forth. I argue that demons don't inhabit inanimate objects, they look for a living vessel. But honestly the Bible says so very little about the nature of demons, their origins, etc. The Catholic Church seems to have the market cornered on exorcism. Not surprising though, since their theology includes interceding on behalf of the dead. There are certainly things that defy logical explanation. There are a couple of ways you could handle this. You could explain to this couple that you don't believe the house is demon- possessed, but that you would be glad to pray a prayer of blessing in the house. Or you could simply decline to get involved. What always concerns me is the setting of precedent. I don't like to feed superstitious behaviors by accommodating them. I also don't want to be known as the guy who will exorcise your house . That could keep a pastor real busy in a big city