I think a Leatherman or similar tool would get more use. I got my son a Boker Applegate-Fairbairn dagger and Gerber demolition pliers prior to Iraq, as he was a combat engineer. I doubt he ever used the dagger, and it turned out that the the pliers were standard issue. The ones with the blasting cap crimpers...
I managed to get them both back after he was killed in combat. I think a Swiss Army knife would have been more useful, day to day. Best things I sent him in Iraq were Skittles, Starburst and gummy bears candy.