I know some deployed men and women. In Kabul, they can get their mail in 2-3 weeks. Farther afield, it is like being on another planet and mail can take 2 months. Some favorite care package contents:
1) Electronic games for whatever portable game-box your soldier has. These get traded back and forth.
2) We are instructed not to send any homemade goodies. They will be confiscated at the military post office, because of the fear that bad people might hide bad things in them. Remember that your package is likely to experience temperature extremes.
3) Handwritten letters mean so much, and are re-read over and over. Enclose photos for best effect...pictures from home get handed around and admired by all. Send disposable cameras, and ask that they return one of them to you with (undeveloped) photos of their experiences (to the extent they are permitted to take pictures). You will get some amazing, educational photos in return.
4) Paperback books in whatever genres your soldier likes. These, too, will get traded around.
5) Consider throwing in some items he can share with the women. In Afghanistan's dry, dusty climate, women appreciate quality scented hand and body creams, cleansing lotions, and soft cosmetic puffs. Heck, the men probably appreciate them too, albeit with less scent
Choose small sizes, to fit in packs and lockers.
Good luck to your brave nephew.
Amethyst