I know I never write on this stupid blog anymore, but man, I really felt this. He was 88, so it's not as though there was some tragedy to this, but he was probably one of the most distinct and emotionally powerful opera singers ever, and the fact that he is no longer around is really sad.
Something I spent listening to last year, over and over, was his singing of "So starben wir, um ungetrennt" from Act II of Tristan und Isolde. So amazing, and really, it's the part of the opera that you need to hear before the Liebestod to really punch you in the gut, because Isolde is there, alone, singing what she and Tristan had been singing together. I would encourage you to seek it out, to hear that voice of his.