Can he call you collect or do you only have a cell phone? It's very frustrating when you're in jail not being able to call anyone because a) Who memorizes numbers in these days of 'my contacts' lists? and b) unless a special account is set up by you for your cell to accept collect calls from the jail, the only numbers he'll be able to call collect immediately will be land line numbers.
What state is this? I ask because it can make a huge difference on the eventual outcome. If it were California, and this was his first 'possession' charge (or any using charge in general) he'd be out soon and required to attend classes/sessions. The first offense usually results in the person going to a joke-like 'educational' course for a few months called PC-1000, the second involves a more intense course requirement permissible after the approval of Proposition 36, the third...? Not sure.
If you can speak to him, tell him to call a bail bondsman (or you do it with his info) in order to find out exactly what he's been charged with and so forth. I'm pretty sure he'll be out soon. But yeah, it does suck to be there. I spent 11 months in county for multiple drug-related charges as well as DUI. I never took the first couple of 'get out of jail free' cards they handed me that I described above seriously. Never even went to a single class. So that ultimately didn't help me either.
Chin up, all will be well. If you want to look out for him as best you can in any way you can starting now, make sure he has some money on his books so he can order commissary (extra food, shampoo, razor, cookies, whatever). It's a pretty good feeling hearing them call out your name for an order you placed even though you doubted you had or would be getting any money. It says, "Somebody gives a shit. My friend!"