You only have to search his name on Youtube to see the state he has been in over the last few years. It's very sad - I was a great fan in the early 70s
Let's take a step back...he's had a great life. He's been a teen idol, a successful actor and made millions of people happy. He will be remembered for a long time by many fans all over the world. All in all, not a bad life.
I think at times like this, we shouldn't feel sad for the life that he won't continue to lead, but happiness in the life that he has had.