He Said He Was the Healthiest Man. Then Came a Diagnosis (nytimes.com)

Subtitle: "Bryan Johnson, the longevity guru, wants to live forever. But the big question is why."

Answer: Duh, that's why. If you're perfectly healthy and doing what you enjoy every day, then on which day exactly do you plan to say "time to die?"

I don't have an NYT subscription but I'm familiar with this story. I think it's a bit blown out of proprtion... autoimmune gastritis is not a death sentence. I think Mr Johnston will probably find plenty of ways to cope with his vast wealth