Will your vet do house calls or could one of the vet techs come to your home to at least help you get him in the carrier? Maybe you could ask a friend or a neighbor to help you with him. Hopefully you'll be able to get him into the carrier some how and he'll then be able to be seen by your vet and then hopefully the vet will realize that he's the kind of cat that must have some kind of a tranquilizer. Good luck.