I think you need to strongly encourage your wife to inform HR about it. The kid obviously is immature and has no clue as to what he has done. If he gets fired, he deserved it. I know your wife is intelligent enough to not take it seriously, but for her own sake and the other women in the workplace, a stand needs to be made.
If she doesn't want to tell anyone at the workplace about it:
Return the flowers at work with a hulk hogan shirt ripped right down the middle and shredded to pieces and see if he gets the idea..
