Question: What is the date of death of Robert K. Von Weizsäcker's father?
Sentence (from "Richard von Weizsäcker"): Richard Karl Freiherr von Weizsäcker (15 April 1920 – 31 January 2015) was a German politician (CDU), who served as President of Germany from 1984 to 1994 (of West Germany 1984–1990 and of the reunited Germany 1990–1994).
Relevant evidence: Yes