Nobody think he simply has shitty genetic for muscle AND for dieting.
He has been followed by many recognised guys, even a natural one who admirably justify his results with his hardcore training and optimised diet (but can't apply his knowledge for another person).
It can't be a problem of short-term or long term-memory, he seems to know what he has to take to build muscle (and fat) or lose fat, he should know what are the basic proportions of carbs, fat, and proteins a man of his size must take after 5 or 6 years of training.
People who follow him may be a little bit coward in rejecting the fault on him all the time, as if he applied the opposite of the prescribed program.
You can easily see he loses weight during his prep, but his loss principaly come from muscle mass, and that happens even with top pro-bodybuilders, so imaginge with the worst gifted person in the world.
Your program simply doesn't work and it's not the only one. If you were aware of his mental problems before preparing him, why didn't you take all the precautions to be sure he will follow your plan ?
I think you took all the precautions required, but as it's a total fail, now you blame him. Maybe you don't realize that without the supplements you use to get in shape, you can't transform a donkey to a horse.