I worked as a health care assistant and was really irritated by some families of very old people I worked with, policing their diet. If there's a real health reason for a particular diet or certain foods being a no-go area, fair enough, but if a very old person wants biscuits with their tea, a piece of cake in the afternoon and a bit of ice cream for dessert in the evening, then I for one, wouldn't stop them.
As someone upthread pointed out, dementia (even mild) increases the desire for sweet things in many people. It's one of the things that triggered alarm bells when I was looking after people - if they began upping their requests for sweets, chocolate, cake or wanting no main course but just pud.
At 92, as far as possible, people should eat what they like, if they are mentally able to make a choice. Definitely they should be encouraged to have enough protein, calcium, healthy carbs and fruit and veg, but sweet stuff is often important for an older persons quality of life sometimes.
I had one post-operative patient, whose family were treating her like a small child, telling her she couldn't have the trifle she really wanted, because it wouldn't help her recovery. She was being picked on so much, she was in tears, the poor woman. I could have whopped them, I was so cross and tactully pointed out, that when people are recovering, it's normal to not fancy or cope with the thought, of a lot of things, and that it's more important at this stage just to get calories down for energy and to try stimulate the appetite any which way. Arggggh.