Would a guy want a second chance with a girl he never got a chance to be with?

High school- freshman yr, I got the chance to get to know a guy that I eventually had feelings for after he had feelings for me. The guy and I had huge hilarious plans of kayaking and building a treehouse and more... But when I talked to my BFF about him, she got super jealous and tried stealing the attention, which turned me and the guy both off and we just kinda stopped talking. I'm building a treehouse now, sophomore year, for the younger kids in my neighborhood. He's had a few girlfriends in between our crushes, but they lasted for really short amounts of time. Lately he's been lookin at me in the halls, but he never tries to initiate contact. Should I ask him to help out with the treehouse? Would a guy generally want a second chance with a girl he didn't get to be with? And please, do not say I need a new BFF, I have that situation worked out. Thanks for your answers!