Hello dkulamsal, Post malaria patients generally complain of loss of appetite, it is a common complain. Loss of appetite occurs due to the bitter quinine medicine they have to take to get well. The treating General physician should have given vitamin tablets. Anyways it is not always medicines that help to recover, it is the well prepared nutritious home made food that is best suitable for an elderly person. Give fresh green vegetable dishes, fruits, nuts and eggs. They are rich in vitamins and mineral contents. He needs vitamin B and E. Papaya is a very good natural food that increase appetite, it has enzymatic actions. Dairy products and porridges will do good to him. Fresh food have greater potential and aid recovery better. You can give milk and energy drinks. Well cooked cereals and legumes will add to his health benefits. Take him for a walk in the morning so that he gets toned up and feels good. Continue the medicines the treating physician has prescribed. Your father will get well soon. Have a good day.