He was short of breath because of his asthma, not a choke. I personally know an asthmatic that died from shortness of breath, no one touched her neck, no choke needed.
There is a reason jr high and high schools do not allow obese asthmatics to go out for the wrestling team.
I'll make sure to pass your diagnosis on to the person with a medical degree, who actually examined his body & the evidence, then ruled it a homicide.