The Legends Club by John Feinstein has the subtitle Dean Smith, Mike Krzyzewski, Jim Valvano, and an Epic College Basketball Rivalry and covers well the three men, and particularly the relationships between them.
A commonality between the men seems to in their character, with one example Smith decades ago telling Feinstein that "you should never be proud of doing the right thing. You should just do the right thing" and another Valvano's speech at the 1993 ESPY Awards just prior to his death from cancer. The interactions written of between Krzyzewski and Valvano prior to him dying and then later between Krzyzewski and Smith prior to the former North Carolina coach dying were the most compelling parts of the book, first with Valvano undergoing cancer treatments at Duke and Krzyzewski often at his bedside and then Krzyzewski spending time with Coach Smith as he suffered from Dementia prior to his death in 2015.
There was definitely some poignant scenes written of the book and Feinstein seemed to do a very good job writing about the men, their competition with one another, and their coming together.