On Wednesday, Erin Popovich, San Antonio Spurs head coach Gregg Popovich’s wife of 40 years, passed away after a long battle with a respiratory illness. Few in the media were aware of her medical condition. Popovich’s philosophies on the game of basketball and, increasingly, his sentiments toward the president are common knowledge, but he has carefully guarded his private life.

There’s not much information about Erin Popovich’s life available to the public. She was 67 years old, and met Pop through her connection to the Air Force Academy. Pop graduated in 1970, and Erin’s father, Jim Conboy, was the Academy’s athletic trainer from 1955 to 1997. She was, according to the San Antonio Express-News, a childhood friend of Betsy Gwin, whose father, Robert McDermott, was the Spurs chairman who hired her husband to be the team’s general manager in 1994. (He would take over as coach in 1996.)  According to the Express-News, the illness that she had lived with since the mid-nineties kept her from making appearances alongside her husband. The couple had a very private family life, so much so that it made headlines in 2012 when Pop mentioned his wife on an ESPN radio show. She would, he said, tell him to be more mature during his famously cantankerous exchanges with reporters—advice that, in recent years, he seems to have taken.

Erin Popovich wasn’t a public figure, in other words. But we like the way that Hall of Famer Steve Nash put it on Twitter:

The outpouring of support was a reminder of what Pop means to the league, and the outsize role that its longest-tenured coach occupies in the NBA’s culture. LeBron James, who agreed to speak to a sideline reporter about his reaction to the news last night, expressed that in a live broadcast. “The NBA family, we all stick together,” James said. “I know we compete every night, but when something like this happens it really puts things in perspective.”

According to ESPN, several of Popovich’s fiercely loyal players were with him Wednesday night—both Tony Parker and Manu Ginobili visited Pop’s house, even as the team prepared for a vital playoff Game 3 against the Golden State Warriors Thursday evening.

Pop won’t be on the sideline for that one. Assistant coach Ettore Messina will coach in his stead. It’s a difficult time for the Spurs—an organization that, because Pop has had a tenure of more than two decades, is especially familial—and with the series returning to San Antonio, we’ll see what the organization does to honor the memory of a woman few in the wider NBA community knew well, but all are mourning today.