I can't give you anything specific to AL, but in the states I've worked in, carrying a concealed firearm is only a misdemeanor. It's a firearm related misdemeanor, so it can prevent you from getting a license to carry a gun, and other things like that.
If he was in possession of controlled substances, and not "Selling" them, or carrying them for sale, then it's likely that is either a misdemeanor charge, or a low grade felony at most.
In which case, if the carrying had NOTHING to do with the drugs, it's very likely that they may only charge him with one or the other, whichever one is easiest to prove, depending on the disposition of the District Attorney.
It's also possible, that if he "turns snitch" they might not even charge him at all, and just "hold" the cases over his head as long as he keeps turning in information which leads to other arrests.
Completely depends on the DA and LE agency policies in your area.