Complex sentence: Her brother, Charles (1898--1971), was born in the island of Jersey, used the surname Wendling which was borrowed from Rose Wendling who was Jean Chauchoin's paternal grandmother.
Split into simpler sentences: Her brother, Charles (1898--1971), was born in the island of Jersey. After grew up, he used the surname Wendling which was borrowed from Rose Wendling who was Jean Chauchoin's paternal grandmother.