I used to use brain gym to help me get to sleep. It is especially helpful if he stays awake because his mind is going over and over things. Once I use it I am usually asleep within 5 mins.

Start by putting your hands together like you are praying except only your finger tips are touching. Move your fingers in and out and concentrate on trying to balance them so each finger tip is touching their 'friend' from the other hand equally and balanced (ITMS). Do that for about 30 seconds. Then put your hands together like praying again except flat against each other (palm to palm). Then have the hands grasp each other and you fold them through. Hard to describe so see a link with a picture here: Mirasol Newsletter | April 2006
The lady under the heading brain gym a total workout for your mind. While your hands are folded over, look closely at the fingers and how they interlock and how each hand is connecting. Do this for 30 secs. Then repeat both exercises again.
I find it really effective and easy but hard to describe so I hope this made sense and can help him.