Afraid the voice is gone forever, from what I understand. He had some vocal cord polyps or something similar several years ago, and they were pre-cancerous. I think on doctor's orders he was strongly advised never to sing again, although another rumor I heard was that he is graduallly getting his voice back and may attempt singing again one of these years. Time will tell, but judging just from the way he talks in between songs, I doubt singing is on the horizon anytime soon.

Gene