‘Extended Family’ inspired by real-life relationship of Celtics owner, wife and her ex

Boston, Dec. 25: When Boston Celtics owner Wyc Grousbeck felt like his life could be the premise for a television sitcom, he knew just where to turn: His friend Tom Werner, a Red Sox owner and TV veteran who was behind megahits like “The Cosby Show,” “Roseanne” and “That ‘70s Show.”