I can second the "hurry up and wait" mentality of the AF. And that's your whole career, not just BMT, lol.
Also, the new(er) version of Basic is supposed to be a lot different than the previous one. It's two weeks longer now than it used to be, and from everything i've been told most of the detail oriented things (like spending hours learning how to properly roll your shirt) has been done away with in favor of more combat oriented training.
As mentioned, his recruiter will (if he/she hasn't already) provide him with a list of what he needs, what is approved, and what is not allowed. Things like cell phones can be brought, but will be locked up. Calling cards are a good idea, as pay phones are available throughout the process. When my ExH went through, he called me once a week, and wrote about as often. That sort of thing all depends on his TI and how his flight is progressing/behaving. Letters and phone calls are a privilege there. If you get a tough TI, you may not be allowed, or if something happens with your flight they may be taken away.
Everyone i've ever talked to has said it wasn't as bad as they thought, and most of them said they ended up enjoying it a few weeks in.
Near the end of Basic, he'll get his job and orders to his station for Tech School. There is no break in between the two, he will be sent straight from Lackland to his school location.