Should I tell him the profile is fake?

My friends found some pics of some girl and made a fake Myspace..now they talk to all of our friends and some of our friends' friends. They talk to this kid and he wants to hang out with this 'girl' and I feel so bad for him because he thinks she's real... I really want to tell him it's fake (even though I don't know him) and I'm thinking about it but I don't know if I should and ruin my friends fun? But they're having fun at his expense..I feel really bad. please help!

what he doesnt know cant hurt him. as long as its somebody you dont know then who cares if he never knows? his feelings wont be hurt because he wont know. and its myspace, its not that serios, its for fun lol