Complex sentence: The family survived their father's regular bouts of unemployment, gambling and alcoholism with the help and support of their grandmother and latterly from his sister's employment as PA to the London Vice President of Morgan Guarantee Trust Bank.
Split into simpler sentences: The family survived their father's regular bouts of unemployment, gambling and alcoholism with the help and support of their grandmother and, also his sister. Who was employed as a PA to the London Vice President of Morgan Guarantee Trust Bank.