My hubby is the XO for a basic training unit. You'd be surprised at some of the things they have to "dispose" of. The first thing they are told is what NOT to bring... and those that bring that stuff get a tongue lashing for not being able to follow directions from the get-go. Some good items... writing material, phone cards, some money for when they are allowed to use it - depends on what phase they are in - they can bring cell phones and earn them back, but many of them turn up missing, or get stolen. No watches, jewelry, etc. Foot care products are a must, as well as a couple of sharpies. Black. To label EVERYTHING.
Less is better. Once he gets to his AIT, he will be able to have more. It's less strict.
Where is he going to be for basic? (I wonder if my hubby will have him. lol)
Just wanted to add... have him bring a cheap watch, just in case he is allowed to have it. Every place is different. BUT, it needs to be able to withstand water, mud, being tossed around, and beaten up.