My b-i-l is in a similar situation. He's in his 70's now but says it hurts so bad that he wishes he would/could die. And he's not expected to live more than another three years anyway because of blood disease. He starts crying whenever the subject of his health comes up. But, he would never take his own life. It would be an entire different scenario if a person was in their 30's or 40's
I can't imagine how much pain he is in because I've never experienced a great deal of long-term pain. If I was in his situation, I think I'd feel about the same, but wouldn't go through with it.
So sorry he's going through what he is.