S.H.
Doe he play electronics?
The back lighting, of electronics, actually causes stimulation and interferes with sleep.
I actually read that, in a magazine.
Or, does he drink soda or things with caffeine? That same article said,t hat kids this age drink soft drinks and it has caffeine in it of course, and it simply is not handle well, by children and Teens.
It, interferes with sleep and causes other problems.
What he can also try... is 'deep breathing' techniques. Look it up online. But things like deep-breathing and Yoga/meditation... shows actual clinical improvements in a person's brain movements. It... does relax a person. And helps with anxiety as well.
Or... go to a Naturopath Doctor. And per your son's issues, there will be natural alternatives and solutions.