1. She is hot. Yes, unless she is half ogre, he likely thinks her attractive. But that is no reason to worry or freak out. You can be attracted to someone without ever acting on it and without having actual romantic feelings. Unless he is a cheater, he can think someone is hot without acting on it. I’m sure you do it all the time.
2. He doesn’t even notice. It is true. Some guys literally do not see some of their female friends that way. I mean don’t you have some guy friends you truly think of as a brother or one of the guys. He may have female friends you are worried about, but he could be entirely clueless to them being attractive.
3. He has fantasized about them. Sorry to break it to you, but it is true. Just how many guys have fantasized about their elementary school maths teacher, babysitter, and best friend’s mom, it has happened.
Again, this does not mean he is into her or has any urge to act out these fantasies.
4. He gets turned on easily. Girlfriend or not, guys get turned on by women’s features, even women they shouldn’t be turned on by. One of his female friends may be wearing a low cut top. He doesn’t actually have to be attracted to her to be turned on by her cleavage. Just remember you trust him and that’s what matters.
5. He has thought about her before. There is definitely a chance he has thought about asking her out in the past. But once you came along, that thought likely left his mind.
For some reason, there is always some sort of history or tension between men and women that are friends. But that doesn’t mean that it means any thing now.