The cop say he didn't believe him when he said he couldn't breath
According to the training I once got for doing the Heimlich Maneuver, if the person can speak, then he can breath. Just saying.....
When somebody you are crushing or choking says "I can't breathe", they obviously mean that they cannot breathe
freely.
Actually it's quite possible he couldn't breathe, but it was not because of the maneuver by the police officer, it was because of his health problems.
However police run across many people making the same claims. They are simply trying to stop police from subduing them by creating a false condition that may make them stop.