Complex sentence: He gives his friend up to the Nazis, who burn him alive inside of a synagogue, and covers up his pain and fear of having effectively murdered this friend by taking on the persona of an anti-Semite.
Split into simpler sentences: He gives his friend up to the Nazis, who burn him alive inside of a synagogue. He later covers up his pain and fear of having effectively murdered this friend by taking on the persona of an anti-Semite.