Hi Peatrolover22,
I don't know if this is the advice/answer you were hoping for but........here it goes:
Your friend (like yourself) is going up and getting different feelings. Hormones kick in, and the body changes. During these changes (and after them too), people start feeling a special way for somebody. And for your friend; it happens to be somebody who's mean to you. I can see why you want her NOT to like this guy, but you can't really control your friend; can you? She's going through those stages, and the special feeling has taken over. It happens alot, and you can't stop it.
It's natural for her to stick up for somebody she fancies, but she should feel ashamed that she didn't even consider you for a moment. Alot of times, boys can ruin a friendship between girls.
Konw what I suggest? If you want to still be her friend, then only hang out with her when that guy isn't around. That way, he can't interferre with your friendship. Keep this in mind: Friendship lasts longer than love. Your friend is still young and has tons of time for relationships, and young love hardly ever works out. That guy will get bored of your friend sooner or later, or vise versa. Your friend will come around when she's ready.
As I mentioned before, your friend is going through changes and her feelings are developing too. Guys often take priority in a girls life, and she may not realize she's ruining a friendship.
Remember to always comfort your frined if things don't work out. You may feel angry at her; but don't let this guy mess up your friendship. It's not worth it.
*Tgd*