T.K.
I used to have terrible insomnia as a teen. I started trying to meditate in my 20s and discovered a great technique for falling asleep. I've taught it to my 3 and 4 yr old. When you are learning to meditate they tell you to concetrate on your breath. It's soooo boring (relaxing) and it totally quiets your mind. It tricks your body into slowing down and going into a restorative state that makes you very sleepy very quickly.
Tell him this... quietly and slowly and calmly.
Breathe in through your nose and out your though your mouth. Watch the chest rise when you breath in and fall when you breath out. Concentrate on beathing slowly and deeply. Breath in until your lungs are completely full and then breath out until they are completely empty. Everytime you find your mind wandering somewhere else, just gently take it back to concentrating on your breathing. Breathe slowly and slow your body down.
Next thing you know...zzzzzzzzzzzzzzzzzzzzzzz