Despite him being sick now he has amazing resiliency. His main issue isn't even gear related per se, a back injury like his could happen to a natural. Then there was his hard headedness of stressing his broken back with heavy loads to the point of breaking screws in his back. There are natural or semi-natural athletes with similar issues, like I saw some reel of Bas Rutten where his one side is atrophied due to some spine issue. Lots of others would have died decades earlier from organ problems if they'd juiced as hard as him. I'm sure he's probably already taken a bunch PEDs to recover, maybe even under doc supervision 
I suffered similar injury blew at discs at three levels, lost my entire rights side, pec lat delt arm opted for replacement over fusion unlike big Ron I haven't trained heavy ever since and I was already retired. Hell of an injury and surgery process, rehab with nerves takes years and it never comes back im 18 years post op, there is still an inconsistency with fullness left to right and a weakness all be it much better than it was at the start, where there was a 4-5 inch difference in left arm to Right arm.
My taking gear days were over but even if I did grow or put weight on it favoured the side unaffected by nerve damage, causing more issues, have lost money, businesses relationships but that was a very tough time mentally for someone like me who's been training all my life. He has my sympathy for his injuries but there is no coming back to competitive bodybuilding from nerve issues on that level look at Jay, Priest they have suffered same.