Sorry to read this sad news, I had the pleasure of corresponding with him breifly about eight years ago by e-mail after reading his biography of Mahler.
We discussed Das Lied and the 9th symphony and thier philosophical meaning. His book is a pleasure too read, insightful, informative, with a down to earth feel to it.
He has given me a greater understanding of Mahler's music, and am very gratefull for it.
Vatz