His anger at his mother for leaving his father. When my father left my mother I was angry for about, oh, five years, and it took a lot of effort on my father's part to repair our relationship. Some confused gay boys mistake their feelings for men as a rejection of women, and act out accordingly. Other gay boys, unable to tell their friends and families the real reason they don't want girlfriends, cop an attitude about women. His life of crime.
Some teenagers engage in anti-social behavior in order to attract attention to themselves.
He may not be able to ask for help, but he can create circumstances where he's going to be helped whether he appears to like it or not. Then again, you may not. Some folks, regardless of anger, opportunities or the amount of support they get at home, run around stealing cars. It's a mystery. If you ask him directly if he's gay he'll probably say no, and once he's gone on the record with no it's going to make it that much harder for him to come out.