Honestly, more information on the situation is needed. I am not saying this to be mean but does he do alright with the ladies or is he kind of a dork?
If he is kind of a dork, you are screwed.
If he is an alright looking kid who has decent social skills, make a one year deal with him. Tell him to go away to school for one year, and if he still feels the same next summer, you'll totally support him.
Trust me when I tell you, if he is an alright looking kid who discovers co-ed dorms and beer, he won't even remember his current honey's name until he needs a summer time booty call.