Hi Sarah,
It may all be in your head. It is unlikely that this guy likes you.
He has known that you like him for several months now and hasn’t done anything about it except look at you.
He has turned down the opportunity to talk to you and when your friend asked him about whether he liked you, his answer was vague.
Again, his behavior would indicate that he doesn’t like you.
You may be too hopeful about this guy.
Regardless of how shy you think he may be, he should have made some kind of move on you once he found out that you liked him.
Oftentimes, shy guys are primarily afraid that they will get rejected by a girl if they were to talk to her.
However, once they know that the girl actually likes them, they are often more willing to take a chance on talking to the girl.
He isn’t shy with other girls. He is able to talk to them without any issues.
Hence, he already has the conversational skills necessary to talk to you and yet he hasn’t.
All of this would indicate a lack of interest in you.