"It makes you think, who cares if I die of lung cancer? Because you can go anytime, anywhere, anyhow."
Hopefully, when the shock has subsided, he will reconsider this statement. Maybe he doesn't have anyone to care, in which case he is still choosing a prolonged painful death. Assuming he does have someone to care, his attitude is totally selfish. They won't want to watch his suffering.
I hope he recovers from the trauma and is able to think rationally about living well rather than dying badly. I hope he has people to care about him and I also hope that he doesn't wish to test their love by putting them through weeks or months of distress.