LOL. I did that without the news coverage. 300lbs wasn't pretty the first time I hit it. Yeah, it will be hard to get off if he doesn't have a fast metabolism. Gaining that much in that short a time frame is also not a good idea. That is why his body is reacting that way.
This is only a good idea if you know you have a fast metabolism and can already get away with food most can't.
I could see if he was going to make use of this "bulk" and try to gain more muscle, but doing this AND quitting the gym is just bad all around. It will be way harder to lose as a result seeing as he spent his whole life NOT doing this.
Someone who had trained their body to accept massive calories and was using most of those calories for muscle growth would possibly see a way easier time getting back in shape.