Steroids are drugs, specifically agonists, just like ecstasy and methamphetamine. Just like how a methamphetamine addict's brain will try to reduce the dopamine in the system by producing less dopamine and shutting down receptors, people who do steroids, clinical or otherwise, will develop hypogonadism, which basically means that the testicles will literally become smaller and produce less testosterone. This is why people that aren't fucking retards "cycle." For instance, I use steroids, I am open about my steroid use. Specifically I do 8 weeks of 160mg testosterone cypionate, which is considered a pretty mild juice. During those 8 weeks my testicles verifiably produce less T naturally. To recover, I take 12 weeks "off cycle" and take other medications for PCR or "post cycle treatment" which includes stuff like clomid, which will suppress your natural estrogen to reduce the negative side effects of steroids. These side effects include being moody, low energy, cramps, sore nipples, etc. They suck. This is why faggots like Goldman just... Don't... Cycle. Lmao. They don't like the feeling of off cycle after feeling like an absolute god on cycle so they just keep juicing. The problem is that steroids cause water retention in muscles. For short periods of time this isn't an issue. Part of post cycle is to lose the water weight. If you don't take a break, however, your muscles will stay swollen with water, which is bad when things like your heart are muscles. This is why so many bodybuilders died of heart problems after turbojuicing for decades. This is why Arnold has heart problems. Additionally, extremely high T levels can cause blood clots and strokes, another common killer of old bodybuilders.
Trenbalone, colloquially known as "tren" is one of the more well known and dangerous steroids. For instance, the anabolic rating of testosterone cypionate, or "cyp," is 100, tren has a rating of 500. Dianabol or "dbol" is another one that is several times more potent than cyp. Testosterone propionate, or "prop," has a similar rating to cyp but has a shorter half life. For reference, men with low testosterone will regularly be prescribed cyp or prop.
The reason his body looks like shit is because he does a shit ton of steroids and doesn't work out. The steroids will help your body eat fat and build muscle, but you will still look like shit if you don't actually hit the gym and manage your macros. He obviously does not.