Ok, if family medicine won't take him on, you still have the patient relations department to help you and they CAN get things moving in the right direction as well. They can also help with the records like I said. You can get them sent to the doctors you saw there (so they can see what went on and re-evaluate him again) and that won't cost you a dime (make sure you tell the patient relation person this as well, why you need them to see him again). Duke also has a pain management facility. Now I don't know if you do or don't have to be referred or not but it also falls under their Neurology department so you might be able to come at it from that perspective without a referral as well.
I can sympathize having to travel long distance for care, good care. Not now but in the past I drove 5 hours (6 in another instance) just because I demanded good, knowledgeable care. 5 hours weekly (one way) for middle difficult child for almost the first year of her life. I didn't trust anyone in the area at the time as I had been to all of them and also saw the work that was done. It got me/us no where and lots of problems (as well as many others). Sometimes, it's worth the travel when you know what you're getting is going to be worth it!
Don't give up, keep putting your puzzle together and build your village for Cory and bring in help (like the patient relations person- they also have social workers{not the kind you think of} there to help as well).