It seems that X went out to different stage of sleep. It might be that he was sleepwalking or get into REM phase where he woke up. REM usually starts 2 to 3 hours after falling a sleep.

I think there is nothing you should worry about thus I can't be sure and I don't guarantee that my informations are correctly. The best thing would be obviously to go for professional help to check brain activities.

Cheers