I think if he is going to have radiation around his mouth that he should definitely get a PEG Tube. My mother had one put in the same time as she had the radical neck and before radiation. As the doctor told her the Peg tube allows you to concentrate on getting through radiation and not have the additional concern of getting enough nutrients when your mouth is pretty beat up from the radiation. She lost some weight, but I am sure she would have lost much more without the tube feedings.