The autopsy report attributes his death to “being restrained, his underlying health conditions, and any potential intoxicants in his system”

It is an autopsy report.  It is supposed to be based exclusively on medical science. 

You cannot attribute as a cause of death something for which there is no evidence.  “Any potential intoxicants” is something for which there is no evidence.   Therefore it cannot be a cause of death.

The autopsy report is fundamentally flawed and part of an attempted cover up.