Those in the UK especially will probably know of Terry Pratchett, who wrote the Discworld novels, 41 books in total. He was diagnosed with Alzheimer's disease in 2007 and began to raise funds and awareness to fight the disease. Sadly, he died in 2015.
Are you a Discworld fan? I was astounded when I read "Guards! Guards!" - I had heard so many quotes from it through my dad that I felt as if I had read it already! My favourite story about him is that he said he didn't want to get a life because it felt as if he was living three already.