Nobody noticed anything wrong at the time though, no one was saying this. Only with hindsight. There's been many times he's had addiction and health problems since the beginning of Green Day's career, not only during the trilogy time. There's simply no point in speculating about his health at any given time.
The point is you can't judge someone's health one way or the other just by what you think you can tell by observing them. That's for him and his doctor to do. We don't need to try and do it here.