Let him walk away
Where one's military service begins, democracy ends. Soldiers don't get to decide whether they will participate in a conflict and that begins with mandatory formations. When I was in and we were marching in ranks, there would be breaks for smokers. They'd be allowed to "fall out" and puff away. Those who didn't smoke, stayed in ranks. No one got to surf the web or watch TV just because they didn't believe they should smoke.
Sounds like the guy just might not fit the mold of being a soldier. Both he and the military are probably better off if they part company.