Complex sentence: He was the oldest living member of the Rockefeller family and family patriarch from July 2004 until his death in March 2017, the child of John D. Rockefeller Jr. and Abby Aldrich Rockefeller, and the grandchild of John D. Rockefeller and Laura Spelman Rockefeller.
Split into simpler sentences: He was the oldest living member of the Rockefeller family and family patriarch from July 2004 until his death in March 2017. Rockefeller was a son of John D. Rockefeller Jr. and Abby Aldrich Rockefeller, and a grandson of John D. Rockefeller and Laura Spelman Rockefeller.