He had drug addiction related health problems. Might have been an overdose, might have been acute organ failure (eg liver)
My guess is the latter since he was supposedly conscious, cooperative, and throwing up blood when the paramedics got to him.
The Cook Co. coroner just released a report saying this guy died of a massive overdose of oxycodone and codeine. When his private plane landed, the cops were waiting for him. He panicked and swallowed a bunch of Percocet pills so they wouldn’t be found or confiscated — in addition to whatever was already in his system. The cops searched the plane and found 70 lbs. of marijuana in vacuum-sealed bags, bottles of liquid codeine, several guns and armor-piercing ammo and high-capacity magazines.