Complex sentence: He was interred on April 27 in the family plot at Holyhood Cemetery in Brookline, Massachusetts, and was the first of four Kennedy grandchildren reaching adulthood to die prematurely.
Split into simpler sentences: He was interred on April 27 in the family plot at Holyhood Cemetery in Brookline, Massachusetts. David was the first of four Kennedy grandchildren reaching adulthood to die prematurely.