Meh, I'd be bored in a week. It's not like you can't renege on a bet. What's the worse he can do? Treat her disrespectfully, tease her consistently and steal her birthday cake on her birthday? Oh wait, he already did that. F*ck that twat, just study, get into a good university, get a good job and win at life. She's 18 that's just a few years away from getting your own place and getting any pet you want.
Also, maybe get some friends that aren't sheeple who only follow trends and ignore real life.