Shooting them would be murder.
And so should be killing someone while DUI...
The same as if you run someone over after robbing a bank.. it's murder even though you didn't intend to kill someone. In the act of committing the crime (robbing the bank or DUI) you did kill (murder) someone. Intent follows the bullet, or the shot glass..
Or lets take shooting someone as your example.. You go into rob a liquor store, you shoot your gun in the air and tell everyone to get down.. The bullet lands 1/2 mile away killing someone.. You didn't intend to kill that person, you didn't even point the gun at them, but they did in fact MURDER that person.
Lastly, how drunk was the driver?? .08? .12? .24? Was he drunk enough for it to be the root problem, or was he drunk enough for everyone to say it was because he was drunk, and not just an irresponsible ####### what was driving like an idiot and killed his friends?
Hard to believe you can use being Drunk as an excuse to kill somone, but if he was sober he would be guilty of involuntary manslaughter (at the least) and would be doing more time..