Keep in mind that most folks want to do something now (food, etc.) and Dad may be overwhelmed with the amount of casseroles that have shown up on his doorstep. Gift cards for future dinners or waiting a week or so to send something over (when the mad rush dies down) or even preparing a meal once a week for the next several months. If you are close to this family, and depending on how much other family is in the picture, offer to take the girls with you on holiday outings to see the lights, ask them to share Thanksgiving dinner, shopping, etc., so they are exposed to the joy of the season even in their grieving. Play dates would also be good --- anything to help these girls know that there are people who care for them and to help them feel less isolated. If you know the dad well, sit down with him and ask what HE would want you to do for them.