buyer/seller integrity question
I looked at your sale pictures, the body is definitely not "junk". If he bought it based on those pictures alone and didn't ask for any pictures of anything else then anything he found not in those pictures is on him. Clearly he's not buying a brand new car.
There's absolutely no way I'd refund any money. If he wants out of the sale, tell him to bring the car back and you'll refund his money. That's the only deal I'd make, anything beyond that is the buyer trying to scam you.