"...As it turns out (watch the video) the paedo was shot in the head which (I believe) was the injury that killed him...."
No, the head injury is just a graze.
Info about the injuries below.
___________
Dr. Kelley of the Milwaukee Medical Examiners Office conducted an autopsy on Joseph Rosenbaum. Dr. Kelley indicated that Rosenbaum had a gunshot wound to the right groin which fractured his pelvis, a gunshot wound to the back which perforated his right lung and liver, a gunshot wound to the left hand, a superficial gunshot wound to his lateral left thigh, and a graze gunshot wound to the right side of his forehead.