How long will it take my friend to realize she and her boyfriend are NOT meant to be togheter?

My friend has been going out with this tall high schooler geek guy named Michael Stephens who she has been going out with since May. She says he is really cute, sweet, and shy etc. and always pays for the dates, etc. But the thing is he is two years old than her, he is fifteen and she is thirteen. What the hell are they going to do when she is sixteen and hes eighteen?! Going on to the "next level" as they call it would be illegal, and he believes in God and that he is good and that he confessed all his sins and everything so he gets to go to heaven and he wants to grow up and raise a God fearing family and become a priest,etc, etc. Christian dreams. And my friend, Candra, absolutely does not believe in God! She, like me, is a person who believes in Science and if something cant be explained scientifically, than it is something supernatural, that does NOT mean God OR Jesus! She also, like me, says she is a sinner and refuses to confess because what is said to be sins are things humans do as part of their nature, she doesnt lust though. Or at least I hope she doesnt O_O. She even says even if God did exist, he doesnt like God and if she has to go to hell for it, fine, I'll be there, too. And he just says something about she just isnt WHATEVER or something and he even tries to get her to go to Church with him. If he really did LOVE her for who she is as he said he did, he wouldnt try to change who she is. She's Cie, Michael, not a nun. Dont get me wrong, I am EXTREMELY jelous of this dude, but I am happy for them. But I need to find a way to stop this before it turns into an emotional train wreck with that Stephens boy as the conductor and my best friend who I love with 24% of my heart (all that is left over from loving my friends, animals, family, heart used to pump blood, etc.) and I will hurt him all I need to to spare her any harm! But what do I say to Candra? She knows I fancy her a lot, I told her so, and she might think I just want her all to my self. You'd think she would know better since she is my best friend but she and her friends are INSANE. But who am I to say, Im the weirdest guy in the school. If you think someone who wears a Gryffindor scarf, plays "Almost Acoustic Guitar", wears high tops and a black and silver t-shirt he made himself that says "Snape likes Cookies", then yes, Im odd.