Fair enough, my next question would be were their any other drugs in his system at levels high enough to contribute to his death? I'm positive this was addressed in the autopsy, just thinking out loud here. That and his other morbidities made him a ticking time bomb under the right (wrong in this case) situation and the officers provided it. Multiple levels of failure on their part.
I understand the use of the knee in certain situations, it should really only be used to gain control and cuff, if they continue to struggle just restrain them with other means, hobble etc. officers jobs are extremely difficult, taxing work. But indifference and a knee that long combined with his other issues and excited delirium all played a part.