Apparently there is your son talk of fears that keep him awake at night and / or his bad dreams delivery. To solve the problem, have medicines indeed pointless. In any case it is important to give him as much as possible during the day feel safe. It may be that this is a temporary problem. But it can also cause a persistent existence.
Because I know more is not my opinion, the conditions to discuss the issue with their GP. Presumably the doctor knows the way for children such sleep disorder have. Reference to a child psychologist who can see all sides of the issue seems to be the best way. Or it may directly or via a pediatrician can evaluate the general best.