Sounds like he may need to contact the courthouse in the county he was fined in..Some counties you can walk in and pay and others you have to appear before the judge..Good Luck
I not the authority, but the citations sounds legit. Even though it is "deer/bear" season most of the WMA's have special hunts on specific dates so if he was hunting bear last week and there was not a sign in or check in hunt scheduled for that WMA then he was out of season. It is illegal to be on the road with a loaded gun in a WMA, car or no car, during a "hunt" and especially if there isn't a hunt. You can check out all these regs online or pick up a regs book at Basspro or somewhere similar. I believe that WMA's in GA are leased from the forest service and managed by the DNR so the fine should be the same state wide.
Regulated by the Black Robes... DNR writes them but the Probate Court rules on the Fees $$$... No standard Fees state wide, he can call within a week and they'll be happy to tell him how many Benjamins it'll be...