In the case of Boyland, it’s simply pure drug overdose.
This was posted earlier. The other two men had hypertensive cardiac disease which means they died from cardiac arrest due preexisting heart disease.
As to the homicide in this context on an autopsy report it is a medical term that indicates death caused by not natural causes at the hands of amother human. You cannot jump to murder from homicide on an autopsy report as justifiable homicides also list homicide as the COD in the death cert and autopsy report.