What should I doo?

[Volleyballer01]

Okay there is this shy guy, who stares at me all the time. His face gets red and he always looks away when I look at him. He doesn't talk to me, and his sisters always watch me. He will position himself so he can watch me walk away (I saw it in a relection). He smiled at me the other day, but I got shy and quickly looked down and smiled to myself awkwardly. I was afraid he would take that as rejection but the staring continued. However, he randomly just liked one of his exes from two years ago, pictures on Instagram. He did this once before (on a school break too) and I over reacted and tried to make a move on him. He reciprocated, but we kinda stopped the obvious flirting. He doesn't really like girls pictures. Did he do this to try and get a reaction out of me? My theory is that he does this on school breaks so I can't just return his glances, I actually have to put in effort. It's also really close to prom at my school. Did he want her attention for that? Just for reference I don't think I'm being used to make her jealous, all three of us aren't in the same place at the times I pass him and he stares. Please explain without saying just ask him.