Any food suggestions for Dad (90)?

My dad is 90 years young. He wakes at 10 pm, 1am, 3am 4am. hungry. I know in part it is dementia, but I also think that he does better with small bits of food. My husband and I are early 60s. We need sleep.

I pack sandwich parts in baggies - luncheon meats with lettuce, mayo packs, etc. And we leave bread out for him. He doesn't like fruit. Not an option.

We do keep Boost for him.

Any suggestions are appreciated, just to give him variation.