I have to agree with Fun&care. a sleep deprived child sleeps poorly and it just spirals out of control. More sleep. Make sure the parents are not engaging the child. If he wakes at 4am the family (or one parent) should NOT be getting up with him and going about their day or putting the tv on. That just trains his body to wake at that time the next day.

No lights, no talking, walk him back to bed and lie him down. If he's out of a crib then his room should be bare aside from a few quiet toys and books and a gate in the doorway (with the door also closed). A few nights of no interaction or entertainment and earlier bedtime should get the child back on track.

I find when a child has one of these random sleep disruptions (very normal) parents in a sense reward it by getting up with them, putting the tv on to quiet them and it really just trains their bodies to wake up at that time over and over again.

I know one family where they were up every night in the middle of the night (like 1-4am) watching hours of the child's favorite tv show. They claimed it was the only way to keep her calm. BUT they trained her that every night she could watch hours of her favorite tv show with mom or dad cuddling on the couch with her. What child would choose to roll over and go back to sleep when that is an option? The kid wasn't screaming due to anything being wrong...the kid was screaming because for the 13 nights before this night you let her watch tv...'if I scream louder they will put the tv on again'.

Sleep is so incredibly important.