I am with ob1,
It all depends on what he will be doing over there. If he is a medic or administrative non-combat type... I can fill you in. For kicking down doors, convoys and things of that nature, get good weapon lights. At the minimum, a AAA powered LED light on a lanyard is a must so get that requirement out of the way. A Peak or Arc AAA work very well and give him 16 lithium AAA batteries to go with it.
Get him a NiMH battery charger and AAA/AA NiMH batteries, make sure the charger can be used with a 12V automotive adapter. My Maha charger worked very well in that situation. AAA NiMH batteries can be swapped out when using the AAA light for reading, no use in burning up all the lithiums and the dimmer output is fine for reading.
Many people go over there without NiMH batteries or chargers. Tell him to bring at least 20 AA NiMH and around 4 to 8 AAA NiMH batteries. His buddies will thank him for it when they need to feed the discmans, cameras and battery operated speakers. All my NiMH batteries were in constant use by my buddies and he who hath the battery power...has the power!
One other thing, tell him to get a diamond coated knife sharpening device that can be put in the pocket. Everyone has a knife but they forget to bring something to sharpen it. The little things like chargers, spare NiMH batteries and knife sharpeners will make his tour much easier and it will help out his buddies.