Complex sentence: He is the grandson of Mike DePalmer Sr, a legendary coach at University of Tennessee (from 1981-94) who is a member of the Intercollegiate Tennis Association Hall of Fame and a co-founder of the Nick Bollettieri Tennis Academy.
Split into simpler sentences: He is the grandson of Mike DePalmer Sr, a legendary coach at University of Tennessee (from 1981-94). His grandfather is a member of the Intercollegiate Tennis Association Hall of Fame and is the co-founder of the Nick Bollettieri Tennis Academy.