Many times in history it has been necessary to sacrifice the few to save the many, a simple example being the rearguard at Dunkirk.
No reason why moral principles should be any different.
I wouldn't torture the wife (as long as she was incontrovertibly innocent) and children, but I would definitely use torture or drugs or whatever on him.
As I've said here before, if you're fighting a war, them fight it. If you were fighting for your life an hnocked your opponent down, would you stand back and let him get up again?