Is it appropriate to ask mother to clear her place, etc.?

I'm helping my father care for my mother, who's just been diagnosed and is probably early/moderate stage in terms of possible Alzheimer's. She's mobile and can fix herself breakfast, etc., but she's basically treating my dad and myself like servants--holding out the bowl to him to get more ice-cream at night, shoving her dinner plate at me to clear at the end of the evening, etc.
Tonight, she asked if there were any grapes in the house, clearly expecting one of us would get up to get them for her. Instead, I said there were and asked if she would get them for us. I asked politely. She looked taken aback, but then said she would. Is it appropriate to ask people to do as much for themselves as possible, as long as it's done politely?