For a moment there I was like, oh, are they actually going to deviate from the insanely irresponsible cigarette-based romance and make him quit smoking? Nope, not a chance in hell. The doctor said he's totally A-OK to continue chainsmoking!
I drink red bull like water. I've been known to drink pure lemon or grapefruit juice from time to time. I put vinegar on all my food. My diet is ludicrously acidic and pretty sugary.
Apparently this completely baffles my dentist and my teeth should be an utter wreck by now. Every time I go they try to encourage me to use straws or cut down on the highly acidic / sugary drinks.... but I don't, and my teeth remain basically fine.
And I'm the same age as the protagonist.
Maybe it is just the same thing with his lungs. Maybe they're just tough as fuck.