I don't know, others might have a better answer, but what you describe sounds a "little bit more" serious or intense than just a little guy having a vivid dream that upsets him now and again or being overtired. Does he worry about his family being dead while he is awake (does he talk about this?) You don't say how old your son is, was he as old as say momtofour was when she called her dad collect (certain ages more likely for the types of things she was questioning or thinking about than others?) Since he's still outgrowing naps he can't be that old, younger than a kindergartener maybe?
Anyway that would require quite alot of talking and comfort and maybe a bigger plan I would think. Have you ever asked his doctor, or if he's done testing (for giftedness?) asked the psychologist?
