sleeplessness

My son is 15 years, has downs syndrome and strutters a lot. He is lately not able to sleep. In the last 6days he has had about 13 hours of sleep altogether. The doctors dont want to put him on medications for sleep. I took him to A&E when he became very disruptive at home. He was admitted and blood tests were done, nothing was found. He become aggressive,abusive,very agitated,very restless. He is even now wide awake. Has not slept a wink in over 30 hours. We taken him on long walks to tire him out but that's not working. We have an appointment to see the paedtrician at the local hospital in three days. I would appreciate advice on what to do. Thank you.