Dear Wexlar - Your son is fine and will be fine, so do not put your fears upon him. Dreams are our own emotions clothed in images. So do not be afraid of any ghostly hand or arm, go up to it and give it hell.
I have taught huge classes of people and seen such demons met and understood. A man who was in such class while relaxing stood up and ran out f the class. He explained that a dark being was being pulled out of his chest. When we talked it over he admitted that he was frighten of a heart condition. The dark thing was his own fear put into the image of the shape. In my own dream a horde of demons were coming after me. I ran for them and caught one and squeezed it till it cried out. They never came back.
Do not be frightened of dream images. They are your own fears. Your husbands dreams was a reliving of his own childhood fears.
Tony