Raised with my grandmother with Alzheimer for all of my childhood she called me by her long dead brother's name.
Walked out the door one day said "See you later grandma" and she said "Have fun ______" and called me by my real name, called my older siblings and said go spend time, she died two days later.
Walked out the door one day said "See you later grandma" and she said "Have fun ______" and called me by my real name, called my older siblings and said go spend time, she died two days later.
Very common.