I don't trust the PMMA or whatever other SEO these guys use as I think it did Flex in as well. But that is absolutely a separate issue from anabolic or body weight stress or possible recreational drug usage. We need to be clear when lumping everything in together as bodybuilding it is not all the same. These guys are not dying from testosterone.
Dude, he weighed 350 pounds at like 5'11". Even if it was "all muscle" and didn't contain 40 pounds of PMMA and other plastics, that's still a hell of a lot for any cardiovascular system to put up with -- especially if you lift & are active.
Check out his videos. He had a hard time breathing. He keeps gasping like a fish out of water.
Besides, don't you have a 160/120 BP and 110 bpm resting heart rate at like 190 pounds? Your heart would call it quits
long before you hit 300 muscular pounds, even if you never touch SEO or PMMA in your life.