Question: What is the date of death of Friedrich, Duke Of Schleswig-Holstein-Sonderburg-Glücksburg's mother?
Sentence (from "Friedrich, Duke of Schleswig-Holstein-Sonderburg-Glücksburg"): Friedrich was the second-eldest son of Friedrich Wilhelm, Duke of Schleswig-Holstein-Sonderburg-Glücksburg and Princess Louise Caroline of Hesse-Kassel and an elder brother of Christian IX of Denmark.
Relevant evidence: Yes