I've recently experimented with a low dose diuretic, just for 2-3 days running .25,g of Aldactone and I was amazed at the water shed just from that dose.
From what I've read, a lot of guys will dose .50-.100mg for days in a row. Electrolytes being out of whack is a serious issue. At just the dose I took for a few days, I felt off and quit taking it. It does work and works fast though.
I like to think I look at these situations with common sense. Genetics should always be a major factor but obviously with Rich and Dallas they died due to drugs. Dallas didn't have the "heart genetics" but he died from sheer abuse. Rich to be honest was probably lucky he made it to 46 with the things he done. Fact is most bodybuilders deaths are due to drugs and carrying lot's of muscle/weight.
Now this guy to me as Nothuman stated it's likely something acute if at all drug related. But 100% there is a massive genetic component in all of this. You never know what guys are dosing and he could have been abusing but I highly doubt that because look at the guy. He also was very small so it's not like he was carrying around 300 pounds of bodyweight for decades putting huge stress on his heart/body. There was something obviously not right internally with this guy and perhaps the use of diuretics or something else brought that to the forefront and he had a heart attack. It could have simply been him being depleted and stressed so you can't rule anything out. But do I think this guys massive drug abuse killed him... no I don't. Could drugs be a major reason for his death... of course.