I know that proton therapy is a kind of radiation therapy, but I'm not sure how it is different than other kinds of radiation therapy. My dad had radiation therapy on his face and did not need a feeding tube, but I understand this is quite rare. My dad has a very strong objection to feeding tubes, and voiced that quite often. They told my dad he could try without and if he needed a tube, they would give him one. I don't know if your dad will have surgery first, and that might affect his ability to eat in and of itself. My dad's Stage 4 cancer was in his jawbone, and they removed the bone and rebuilt what they took out with bones and tissues from his leg. He was able to eat soft foods after the surgery, and within a few weeks, started radiation. I would definitely talk to your dad's radiation oncologist about his fears and see what they say. My dad had a similar fear of the tracheotomy after his first surgery, and they were willing to try alternatives for his second. They were successful using nasal trumpets to secure his airway instead.