Amazingly gifted singer and like some of my favourite performers, David Coverdale, Steven Tyler, Lou Gramm etc etc, these guys have been blessed to be performing challenging songs into very advanced years. They can't go on forever. Even the likes of Bruce Dickinson isn't too far away from 70.

Sadly, we don't (in my opinion) have many rock icons any more who are picking up the mantle. Glenn has been amazingly blessed to come back from near death for over 30 years of performing since. He's done amazingly well.