D.W.
Cook a meal, visit, clean house for them, offer to do laundry, run errands for them or take them to run errands. Listen to them when they talk. That will often times give you great cues and ideas for things that they may need/want done or taken care of and that's where you could come in.
I just took meals to my bil & sil and my cousins because both of the women of the house are off their feet for different reasons and they are the cooks of the house. So feeding them took the worry off their mind for the hubbies to try to cook and they didn't have to worry about food for a couple of days.