Chicken Soup
Cookies (small)
Chicken stew and dumpling mix
Whatever you take don't take too much. While my husband was dealing with cancer and I was dealing with a severe infection and knee replacements (4 surgeries on one leg in one year), people would bring dozens of muffins, cupcakes, etc. The best food related things we got were a week's worth of meal starters - 3 cups of soup, meals for two or three (already frozen), half a dozen rolls, small loaf of bread. One friend did this twice and it was a great help to have meals already in the freezer. She'd portioned everything out and supplied reheating or finishing instructions.