R.I.P., Buzz.
As for the circumstances surrounding his death, anything is possible.
Haynes is supposed to have been involved in all kinds of drug-related shit - including, but not limited to cocaine smuggling, so he may have some insight. But, notwithstanding his involvement with shady characters and dealings, we should consider some of his other claims such as holding Vince McMahon responsible for the deaths of several wrestlers.
Haynes also places DIRECT blame on Vince for the Chris Benoit tragedy, claiming that Daniel Benoit was actually McMahon's son, the discovery of which caused Benoit to snap.