Please please please look into a few things like Keto Diet and Lions Mane Mushrooms. There are at least 2 other mushrooms that have been shown to increase cognitive ability.
Do a google using Alzheimers, Keto Diet and Lions Mane.
My doctor put me on Lions Mane mushroom capsules about two months ago. Seems to help with memory and brain fog.
I would research and possibly try your suggestion. Unfortunately, I cannot oversee her diet. Although my husband and I planned to bring Mama to live with us, my BIL nixed that in a big ugly way a couple of years ago. (Something about his calling the sheriff because I had “kidnapped” my mother... BWAHAHAHA!)