As a caregiver for my mom who is 90 I found out that the older she got the less she cared about food. Only dinner she would eat would be the meal she ate with us. It's almost another full time job caring for elders and it became much easier when she moved in with us.
Yes, we changed our lifestyle drastically and yes we had children to care for, too.
We tried home delivered meals and they were terrible. Goofed up the order. It as a mess.
There is NO easy answer when caring for elderly. Believe me. We looked.