Has anyone checked her mouth? Perhaps she has tartar, plaque, or sore gums, maybe even a bad tooth that abcessed, and eating hurts?

Canned salmon, canned clams, are both good. Things which have an aroma. A bit of yogurt, cottage cheese or ricotta cheese as a topping (not too much, especially the cottage cheese can cause diahhrea). Chopped olive also is a good topper.