He should immediatley stop watching the movie- do something else- watch cartoons :lol:, sports, anything else that is appropriate.
If he see's a girl- there is a hadeeth about this- but i'm sorry i cant copy it down word for word. " A man is only allowed to look at a women he does not know once"
That means- if he sees a girl unintentionally, he should not turn his attention back on her, and look somewhere else