Unrealistic, or highly unusual, memory loss.
She seems to remember things that are important to the granddaughter. Which is rather inconsistent with the forms of memory loss that I'm familiar with. She forgets that the granddaughters name is Lucy, not Luciano (which is Little Mamá's name). Why would she call someone else by her own name? Maybe it's Lucy's mother's name, too? I feel like I have to make a lot of excuses for this book to make sense.