Any help would be greatly appreciated.
First off: Never mind what he might take with him. Send him a reoccuring package every week, to include a couple of prestamped envelopes so that he can write who he chooses- but include at least one preaddressed to you so that HE can tell you what to continue sending, what to discontinue, and any useful additions and/or changes.
The US Postal Priority cardboard mailers, about a foot wide and a bit longer by about an inch and a half thick offer a good starting place, and the mailer and stamp will cost $3.80 no matter how much the contents you include weigh. I'd include hard candy such as lemon drops and grape, lemon, orange or lemon-lime kool aid, which helps kill the taste of field purified water, and if you can find whatever magazines he favors, that can be a worthwhile addition after about the first half of his training cycle, when things have settled down a bit. One strong suggestion: if you can be there for his unit's OSUT graduation do so. It's an experience he'll not forget.
-archy-/-
Right after graduation, he reports to Fort Gordon for his MOS training. That post seems to be the HQ for the Army Signal Corps. He is a 'computer nerd' who scored 94 on his ASVAB and they really want him to sit at a desk.