I believe he died in an ambulance on the way to the hospital from cardiac arrest. The coroner's report supports the idea that he was not asphyxiated at the scene.
He probably was having some difficulty breathing at the scene but it was not from asphyxiation.
His resisting arrest, the resulting submission hold and his bad health are probably the circumstances that caused his cardiac arrest and his demise.
You are correct.
The fact that many here keep talking about a chokehold and the man not breathing is moot.
A speaking person is breathing.
He died of cardiac arrest.
My guess is this is why no indictment was put forward.
These facts are important.