At Fort Polk, a soldier from another platoon in my company drove a Bradley into a big ass ditch while on the gunnery range. One soldier was killed, another soldier was paralyzed from the chest down and two other soldiers had to be hospitalized. Turns out he had been drinking.
He didn't get a chance to volunteer for rehab. In fact, as far as I know, he's still in prison.
The point being, if he can't stay sober on a training mission, how can we expect him to stay sober on an actual battlefield. In the units I served in, there were no second chances for crap like that. It was too easy for someone to get killed.