Seems like its not necessarily the AAS causing this. But the large amount of lean mass and a specific "lifting" diets along with very strenuous exercise.
Obviously the AAS are allowing the person to get much bigger which in turn stresses the kidneys in many different ways. So it all goes hand in hand. That guy weighed nearly 300 pounds lean also. That's just unhealthy, period.
I do feel the solvents in AAS stress the kidneys directly. Also from what I understand tren directly stresses the kidneys. Where as most other AAS indirectly stress them via weight gain, increase in blood pressure, creating more byproducts for the kidneys to deal with, etc etc.
What I got from this is there is a line to be drawn when it comes to your progress and health. And everyone will be different as far as where exactly that line is. But generally people probably shouldn't be getting too heavy. Seems like body weight is one of the most important factors. I know my body is the healthiest when its lighter and 205-215 is probably about where the line is for me. Although I am quite a bit heavier than that now.
So as far as kidney heath is concerned you should probably not use high doses of anything. You should watch how heavy you get. Stay away from tren and most orals. Make sure your BP is within range. Make sure bloodwork is the same. And have a specific diet that won't stress the kidneys as much as certain other diets will. Drink plenty of water and take a specific supplement regiment consistently. Make sure your cardio is up to par because that's a must imo if you choose to live this lifestyle. Pretty simple shit really. This will help out with your overall health as well. The body is like a fish tank, if one thing is wrong then the entire tank goes to sh*t. Best to keep everything in check so you will be clear.
That's basically what I got. I'm sure there is more to it than what I said.