Complex sentence: They had their first son David and then, promoted to overseas manager and eventually president of Liberty, moved to London while settling his family in Lugano, Switzerland, where they had two more sons, Roberto and Jonathan.
Split into simpler sentences: They had their first son David, and then he was promoted to overseas manager and eventually president of Liberty. Kass moved to London but settled his family in Lugano, Switzerland, where they had two more sons, Roberto and Jonathan.