5 year old ASD son.

My autistic son has trouble falling and staying asleep throughout the night. I get him every other weekend. Sometimes he will go to sleep easily but then around 4-5am he is up and has trouble falling back asleep this happens almost every night that he is home with me.when he does wake up he is in a playful laughing mood. He just lays in his bed and laughs and talk amongst himself. It's 5:30am right now and he's doing exactly that..

I don't know what else to do we've tried turning off TV hour before bedtime, to get him relaxed even tried to lay him down with no TV for bed in a cool quiet room. Nothing seems to really help him stay asleep all night. 

Any advice would be helpful...