Time magazine mentions, in 1938:
Several years ago Adolf Hitler asked the world's greatest otolaryngologist, Professor Heinrich von Neumann of Vienna, to examine his larynx. Dr. von Neumann had as patients and friends England's George VI and Duke of Windsor, Spain's Alfonso, Rumania's Carol, Greece's George, Austria's late Emperor Charles. But he is an orthodox Jew and he turned Hitler down. Last spring, when Hitler entered Austria, Dr. von Neumann was imprisoned and released upon the plea of the Duke of Windsor.Neumann also attended the Evian conference where he tried, unsuccessfully, to effect the rescue of Austiran Jews from the Nazis.
He died in 1939.