When I was going in for the tests, they asked my wife and PA to say what they had noticed in my behaviour. They jointly wrote a letter saying, 'Like any author who's in the throes of writing a book, Terry probably shows all the signs of dementia: he's unworldly, he doesn't pay attention to things, he's antisocial, grumpy.' I'm a typical bloody writer. Maybe all of us have had Alzheimer's for years without realising it.
As a fan, you can greet this kind of news one of two ways. The first is to stand outside in the thunderstorm, shaking your fist heavenward and screaming, "Whyyy?" But after awhile, the rain starts to run up your nose.
His fans, being the stellar people that they are, have taken the second way. They've cooked up a charity to raise money for Alzheimer's research. Pratchett himself has donated a million dollars, and these fans are determined to at least match that sum. You can show your support by spreading the word, buying a t-shirt, or donating outright.
And just because I think they're cool, I'm posting some fan-made buttons from the website. The artwork is apparently that of a fan, and I love Moist Von Lipwig's expression especially. It's sneaky and smirky and I'm not so sure I'd actually give him money.