Complex sentence: By the 1950s, Hermann had settled into life in Buenos Aires with his family; daughter Sylvia became acquainted with the Eichmann family and romantically involved with Klaus, the oldest Eichmann son.
Split into simpler sentences: By the 1950s, Hermann had settled into life in Buenos Aires with his family. His daughter Sylvia became acquainted with the Eichmann family and romantically involved with Klaus, the oldest Eichmann son.