Thanks for your question on Health Care Magic.
I can understand your concern.
He is diabetic and hypertensive, so better to avoid sweet, sweetener, rice, potato, fruits like banana, Apple etc. Also avoid high salt diet.
Prepare his food in sunflower or olive oil. Both are good for diabetes and
hypertension.
Regarding
prostate cancer, food is not an issue.
But maintaining good immunity is important in cancer patients.
So give him high protein diet like eggs, beans, legumes, pulses etc.
Multivitamin tablet containing
folic acid, niacin, riboflavin, pyridoxine,
vitamin b12 etc is also important for immunity.
Zinc, selenium, vitamin C etc are good antioxidants and helpful in immunity, so antioxidants tablet is also recommended in his case.
Hope I have solved your query.
Wishing good health to your father.
Thanks.