Someone help me.

i have a best friend, he's a boy. he has fell in Любовь with soooo many girls in a год and every time, i had to get him out of those situations b4 things got worst. he just told julie, another best friend of mine, that he likes this girl called amy, and he told her not to tell me cuz he was afraid that i'd stop him again. but oen thing that he doesnt know is...that girl is nothing like he thinks she is, she doesnt even respect me. im really scared that if i would to stop him he'd get mad at me. what am i supposed to doooooooooooooooooo? :(