You can also get a gift card or two for a local restaurant with a decent children's menu, if she tells you she is already inundated with food. (When my mother died, we also had way too much food brought to the house. In our case, we were able to freeze it and divide it up among family members, but my dad wouldn't have been able to eat all of that food himself.)
If they need to just get out for a while afterward when all the casseroles are gone, there is somewhere to go. It can be relaxing to eat at a restaurant after a very stressful day of going through belongings or paperwork, and not have to clean up after yourself later.