it also crossed my mind that the situation could be due to something involved with homosexuality.
he could very well feel like he failed his parents, if in his parents eyes, homosexuality is some kind of sin, or evil, or what have you.
if that is the case, then i believe that truly is a shame. i do have my own views on homosexuality, but at the same time, to judge somebody badly because of that, especially someone you are related to, like a child, is just plain wrong.
however, since he hasn't told us, it could be any number of things, and we are all making assumptions. is he gay? did he get a girl pregnant? did he drop out of school / not get a scholarship? maybe he got arrested?
who knows, maybe he was house sitting, and burned down the house. maybe he killed the family dog. crashed the car into a pole. it could be any number of things, and like many posters have said, it's hard to give accurate advice without knowing the situation.