Nutrition is a great question. It is possible that your dad's appetite will be affected by the chemo or that food taste will change. Cancer survivor and dietitian @marykaym63 has some good suggestions in this discussion in the Breast Cancer group:
- Nutrition during and after breast cancer treatment https://connect.mayoclinic.org/discussion/nutrition-during-and-after-breast-cancer-treatment/

Here are some other discussions to read:
– Nutrition and Cancer: Getting protein in my diet https://connect.mayoclinic.org/discussion/nutrition/
– Healthy diets for cancer patients https://connect.mayoclinic.org/discussion/healthy-diets-for-cancer-patients/
– Video Q&A Cancer-Fighting Foods https://connect.mayoclinic.org/webinar/cancer-fighting-foods/

Formydad, Have you had an appointment with an oncology dietitian? They can be so helpful with suggestions.