"Family comes first," Coyotes general manager John Chayka said in a statement. "Our thoughts and prayers are with [Tocchet] as he deals with this personal matter. It's important that he takes the time to be there with his family."
John MacLean, named a Coyotes assistant on July 26, will serve as coach until Tocchet returns.
The Coyotes, who have a 22-35-11 record in Tocchet's first season, are 4-1-1 in their past six games and 10-3-2 in their past 15, including a 1-0 win against the Vancouver Canucks on Sunday.
Tocchet, who won the Stanley Cup as an assistant with the Pittsburgh Penguins in 2016 and 2017, was named Coyotes coach on July 11. He played 18 seasons in the NHL, including three with the Coyotes from 1997-2000.
MacLean, who played 19 seasons in the NHL with the New Jersey Devils, San Jose Sharks, New York Rangers and Dallas Stars, won a Stanley Cup as an assistant with the Devils in 2003. He coached Lowell, the Devils' American Hockey League affiliate in 2009-10, and was named coach of the Devils for the 2010-11 season, but was replaced after a 9-22-2 start.
