Any advice on finding out if someone would be open for a gay relationship?

Hi,

So, I'm almost 18 now, out as gay to many of my friends for about half a year now and finally allowing myself to feel what I'm feeling. Didn't accept myself for years but coming to terms that the road to finding happiness is to deal with it.

A few months ago I noticed a guy at the school I'm graduating off in a few weeks and I fell in love with him, like crazily. Never spoke to him before, but his unique and special style sparks my interest.

He is one year below me but because of the dutch system also graduating this year. I don't have school anymore before my final exams, so I don't see him there and won't see him anymore. I have two friends that know him and they think he's just straight.

I have accepted that there won't be room for a relationship as I have to accept he is straight, but I experience that it's really hard to get him out of my mind, even though that I don't even know him.

Does anyone have any tips on how to get him out? I know for myself that it would be way easier if I'd have an answer to the question if he'd be open for a relationship with a guy, but as he works with good friends of mine and at a highschool stuff spreads around easily it seems not worth it to straight-up ask him. I'd rather have some way of knowing without him knowing it comes from me. I'd love to hear what you think!