#500,000 doesnt buy a lot of lab time
It buys a hell of a lot more than not having it!
Will it find a cure all by itself - no it won't. But it will help.
Will give publicity to this problem and increase research into it - I hope so.
My Aunt and my g/f's father both suffer from early onset Alzheimers. My Aunt died several years ago. My cousin said, it doesn't matter, my mother died a decade before that.
My G/F's father is presently dying. He had broken a hip and, while healing, forgot how to walk. He has frogotten his family. He has forgotten his name. He has forgotten how to speak. He has forgotten how to eat.
I applaud Mr. Pratchett's donation. I hope that they trigger more donations, both large and small.
I know that should I ever suffer from this awful wasting disease I would serious consider ending my own life immediately rather than seeing it disappear before my eyes.