I've seen this in action with a wealthy old 90+ friend of the family. At the time I was very young and thought it was odd how well timed our visit was, with him dying there only a few hours after, doctor at his side, in his home. (Perhaps it was just a nurse?) I distinctly remember the adults whispering to each other about how he was being medicated to take care of his pain, and his breathing; there was a very long pause before each inhale.