His particular form of Alzheimer's turns out to be Posterior Cortical Atrophy ('PCA', aka Benson's Syndrome), which causes the back of the brain to shrivel. It's his goal to keep active as long as possible, but he's adamant about two points. First, that he wants no part of being a test subject where scientists carefully monitor his decay ("I like vultures . . . at least they have the decency to wait until the donkey has died"). And second, he insists that he shd "be allowed to die how and when he wants", preferring the term 'assisted death' to 'assisted suicide'. That will be a sad day indeed. In the meantime, let's be glad he's still among us, still writing, and still enjoying life:
"I intend to go on living for as long as possible, and no one really knows how long that is, because PCA is rather odd, and also I'm rather odd. I have quite a large brain -- although my teachers would line up to tell you I never used any of it very much -- and so I'll keep going"
And, in case you missed it earlier, the new THE COLOUR OF MAGIC movie (which features Tim Curry as a villain -- ah, it's been too long -- and Sean Astin as an Innocent Abroad) ends with a wonderful Pratchett cameo in which they give him the last word.
favorite quotes from the article:
--"self-made ghettos are hard to get out of"
--"We don't run into too many brick walls" (re. his amazement "at how the universe has opened to our inquiries")
--". . . at least [vultures] have the decency to wait until the donkey has died."