All I can say is that there are no shortage of examples of people who get decent (or even very good) results from programs that would probably be far less than optimal for 99% of the population. Sometimes this is genetics, sometimes this is just through sheer will/grit/work ethic. I also don't discount the "placebo" effect that is present in programming. i.e. if somebody really believes in what they are doing they often get better than average results from it.
In his case, I have no idea. Might be genetics. Might be that very frequent suboptimal efforts (ie. never close to failure) seem to work for him. Might be that a consistent approach to his nutrition (28,000 high quality calories per week) has overridden less than optimal programming.
Who knows. Probably a mixture of everything. My guess is that if he cut this in half at a minimum he'd be even stronger