The most important thing is not to give him hard food. I think stew is suitable for the elderly. Make a steamed egg cake, stir it with rice, and she will feel more comfortable when she eats it. Braised tofu with herring, the soup of this dish is used to soak rice. Potato and eggplant mixed with green onions (add water to the steamer, wash the potato and eggplant and cook in the pot, peel the potatoes and grind them into small pieces, put them all in a bowl, add appropriate amount of soy sauce and stir the green onions evenly). I don't believe your grandmother lost her appetite when she ate these dishes with kimchi soup rice or omelet rice.
Finally, I want to remind you, first, let grandma walk more. The worse her legs and feet are, the less she likes walking. If she doesn't like to walk and digest, that's not good, so she doesn't like to eat, because her stomach hasn't been digested yet, as if she had just eaten.
Second, don't let him eat hard. Better make him some vegetable soup with rice. Don't cook the rice too hard.
Third, don't give the old lady anything too greasy. Eating too much is not good. Usually drink hot water and tea.
Usually you can pay more attention to things like health preservation. I still have many delicious recipes that I can cook. Try the method I gave, and wish grandma good health!