That's tough, but not the end like txjourn said!!!
Just a thought, if it's within your ability, try to offer him something to stay in school, maybe a car, with insurance paid, and maybe some gas money, as long as he stays in school, and keeps passing grades!! That would be the approach I would use!! Rather than telling him what he isn't going to get by dropping out, show him what he can have by not dropping out!!!
GL
~Vikes