Since Dr. Amish claims the New Deal economic policies of FDR prolonged the Great Depression (they didn't, that is just a neo-conservative talking point), how does he explain how the depression came to an end?

The reason the Great Depression finally came to an end was through the massive government spending brought on by the United States entry into World War II. It wasn't the free market that brought the Great Depression to a final end, it was massive government spending. Care to refute that fact, Dr. Amish? Or will you finally admit you are wrong about something? Medicine, not economic history.