that is ab gut, caused by taking too much human growth hormones, and taking them for too long. Its causing his organs to grow, as well as all the muscles, everything grows. Soon you'll see gaps in his teeth from his jaw growing.
a bunch of guys from my childhood skate crew got into all this shit years ago. Once you disrespect your body this much (steroids, hgh ect) its much easier to take painkillers, hard drugs and pretty much give up on life.