Complex sentence: His mother is al Jawhara bint Abd al Aziz bin Musaid al Jiluwi, from a powerful tribe whose members have been intermarried with those of House of Saud.
Split into simpler sentences: His mother is al Jawhara bint Abd al Aziz bin Musaid al Jiluwi. She was a member of a powerful al Jiluwi tribe whose members have been intermarried with those of House of Saud.