Have you ever tried relaxation exercises with him? Once upon a time when we were doing Occupational Therapist (OT), a therapist taught my difficult child's slow, diaphragmatic breathing -- we called it "quiet breathing". It came in handy for times when they were bouncing off the walls at night and having a hard time settling down.
The child lays down on their back, hands at their side, and closes their eyes. Then they put one hand on their belly, and concentrate on their breathing. If they are breathing "correctly", they should feel their tummy rise as they inhale (the diaphragm is moving out to allow the lungs to fully expand with air, causing the abdomen to rise), and it falls as they exhale. Having their hand on the tummy really helps them to feel what their body should be doing when they are taking in air the right way. The more oxygen they are getting to their body and brain, the more relaxed they will become.
We do this for about five minutes or so. difficult child 2 got so that all I'd have to say is "time for quiet breathing", and he'd be yawning after about three or four deep breaths, and on his way to dreamland a few minutes after that :smile:
