Punch him in the face and tell him you were just playing.
As a former 18 year old, this is what I would want you, as a mother, to do: Talk with your daughter about your concerns, and then let her make the decision to stick with him or not. If my mother tried to break up my girlfriend and I, the ♥♥♥♥♥ would have hit the fan and the whole house would have been a mess!
I know people like the one you're describing though, and they are a bit annoying. I have a friend who is into rough horseplay and it just gets old after a while. I've had to tell him multiple times to ♥♥♥♥♥ off. He has calmed down with time, fortunately. Something so simple as messing with personal space can ruin a relationship.