The NBA world was saddened to learn that Don Nelson passed away on Sunday at 86 years old. "On Sunday morning, our beloved husband, dad, grandfather, and great-grandfather Don Nelson peacefully went to be with the Lord, surrounded by his loving family. Hall of Famer Don Nelson, three-time NBA Coach of the Year and five times a champion as a player with the Boston Celtics, has died at age 86. Without Don Nelson, the Mavericks may have been stuck in the cellar of the NBA for a lot longer. Mark Cuban helped turn things around when he purchased the team in 2000, but without Nelson, there is no Dirk Nowitzki, and without Dirk Nowitzki, there is no Dallas Mavericks basketball.