My grandfather started playing piano at the age of four. He taught music as an adult. In the last years of his Alzheimer's, he didn't know who I was and could

My grandfather started playing piano at the age of four. He taught music as an adult. In the last years of his Alzheimer's, he didn't know who I was and could barely remember conversations we'd had 5 minutes prior. But, if you put him in front of a piano, he could play songs for hours.