Lo siento para las dificiles de su padre.

Where is your father's cancer located? If it is in his head or neck, these side effects are totally typical. Please know that daily radiation causes a person to feel very tired, which can cause depression and the desire to stop treatment.

Perhaps you can convince him to try a soothing liquid such as horchata or a liquid meal like Ensure? This would provide nutrition without being so hard to swallow. If he felt a little better, he might be willing to go on with radiation.

Can you speak to his doctors and ask them to tell the family how important it is to finish all treatments?
Sue