Company could have offered him a different job, like sweeping, and if he then refused, let him go. If he blacks out he could hurt others and how the hell are you supposed to move a 420 pound unconscious guy if he’s passed out and maybe in harm’s way in the factory?
Besides the guy doesn’t give two craps about his life if he’s diabetic and 420 pounds. He is eating too much and too much of the wrong stuff. You have to eat a lot to be able to maintain 420 pounds.