Complex sentence: The most influential member of the Royal family is the King of Saudi Arabia, currently King Salman, who chose first his nephew and then his son as crown prince without consulting the Allegiance Council.
Split into simpler sentences: The most influential member of the Royal family is the King of Saudi Arabia, currently King Salman. Although current King Salman first chose his nephew and then his son as a crown prince without any consulation with Allegiance Council.