People do weird things in dream like states.
My dad said he came into my room one night and said that one of my eyes was open and it was following him as he walked around my room. i don't remember anything though. Is their a name to this...uh...condition?
Rapid eye movement.
That sounds kinda terrifying lol but maybe he hallucinated it since it was dark, or your eye somehow opened because of muscle contracting reasons. All our eyeballs move during REM stage of sleeping, not necessarily following him.