Complex sentence: The Salahi & Nuseibeh family are related through Tareq's paternal grandmother (Nuseibeh) on his father's side and to this today continue to be family guardians of the Holy Sepulchre.
Split into simpler sentences: The Salahi & Nuseibeh family are related through Tareq's paternal grandmother (Nuseibeh) on his father's side. The Nuseibeh family continue to be family guardians of the Holy Sepulchre.