Kirk Korver, 27, was the youngest of four Korver brothers, all of whom played basketball at the college level or above.
Kirk finished his career at the University of Missouri-Kansas City in 2013-14, amassing 597 points and 267 rebounds in four seasons as a forward for the Kangaroos.
Kyle Korver missed the Cavs' victory over the Chicago Bulls on Saturday to attend to what was termed a family medical emergency. He returned to score 12 points in the Cavs' victory over the Milwaukee Bucks on Monday.
"I can't [imagine]," LeBron James said at shootaround Wednesday. "I don't have any siblings, so I can't relate. But I do have sympathy not only for my brother, for his family. It's tragic for him to lose a little brother in the fashion that it happened. My prayers go out to the Korver family and everyone that has anything to do with his family.
"I hope he takes as much time as he needs to get back to himself, which won't happen obviously overnight or in the next couple months or maybe in the next few years. The healing process starts now, and we're part of his support group. He has a lot of support here. What else can you say -- it sucks."
"We extend our deepest condolences and heartfelt best to Kyle and his entire family as they go through this very difficult time," the team said in a statement.