I'm curious what you or your husband said when the young man made that comment about hiding a body? If you can afford it, I think it would be a good idea for you and your husband to seek out a therapist for your own relationship and how the two of you are to cope together with this worrisome young man. You don't say how old your other children are, but you will want to make sure they are safe if they interact with him--preferably only in your or your husband's presence. My parents ignored my sibling's strange behavior and their tacit approval only made things worse.