[@Sweven7] He was out in Senior year, at least at school. His parents didn't find out until he graduated, and I've just decided it's a large part of the reason he abruptly left home(though the story he tells is that it was because his parents didn't approve of his band). 

I get the sense that they're more alike than either(or, Billy anyway) would like to admit. So they may have had a sort of double sided relationship. Maybe Connor secretly envied Billy for his ease and self assuredness(or maybe he was attracted to those traits, depending on how honest he was with himself he might not know which), but Billy found him irritating because of his school spirit and insistence on fitting in. Not very fair on Billy's part, but he was a teen.