Don't know how i forgot the tunes! Next to my woobie they were a god send. Also a neck gaitor would be good. I was issued a cotton neck gaiter (I used it to clean my weapon) but a polypro or nice soft fleece one would be nice.
I agree to wait and see what he has when he crosses the pond. Some stuff he will be issued i know some units are getting WilleyX's, Oakleys, Fleece Watch caps (which if he is not issued one send him one worth my weight in gold). Being in the MOS he is he may not get optics for his weapon, or night vision to carry all the time. But when he will need it he should have it (ie. guard duty, patrol, convoy escort). A pair of $20 bino's or a monocular comes in handy when on guard or just looking around. I would not buy body armorer. For several reasons cost, likely to get "lost" in transit, and he should get it. I know when I left over there and my guys left we also left behind 135 sets of interceptor body armor. Send him a disposable camera when you send him a package so he can get some pics.