He could just tell her he can’t show up because he’s afraid or something. Are you sure you talk to people? Nobody would do this to someone they know so well.
He could say that instead of just not showing up and not even talking to her about it. I’m sure she’ll hate him still but at least there’s some reasoning presented
She’s literally doing all of that. Isolating him from other students, including girls of his age so his focus is solely on her, and making him dependent on her for what to do with his feelings and what they mean