Note that the officer's forearm is across his windpipe.
The approved hold has the windpipe in the crook between the forearm and bicep. Simply flexing the muscles cuts off the blood flow through the carotid arteries, producing unconsciousness in seconds without the person panicking from being choked.
This officer knows this. This office has been trained to do this.
He chose to slowly and painfully choke out and terrorize a known asthmatic.
I'd call that terrorism, torture and murder under color of authority.