My Father Hd Given Up On Eating Meals 6months Ago.docs

My father hd given up on eating meals 6months ago.docs gave him econorm sachets fr a couple of days nd his hunger became normal.now again since d past 3or 4 days he is not eating proper food.how can i again give these sachets.how much time before or after meals nd how many times in a day?all his parameters r normal.but his mobility is minimal.he is 85 yesrs old.