Complex sentence: His father, Robert, was a waiter at Sid's, a kosher delicatessen but died when Marty was nine years old; his mother, Dorothy, later moved the family to public housing in Sheepshead Bay.
Split into simpler sentences: His father, Robert, was a waiter at Sid's, a kosher delicatessen. When Markowitz was nine years old his father died; his mother, Dorothy, later moved the family to public housing in Sheepshead Bay.