https://www.sportsnet.ca/nhl/article...ckler-dies-86/
No cause of death given.
Was head coach of the North Stars, Oilers, the Sabres, and the Rangers. Became a GM with the Senators, and was also involved with the Coyotes. He did the Heatley/Hossa deal, and also the Yashin deal that netted the Senators Chara and Spezza (and Bill Muckalt).
Also coached the Canada Cup teams in 84 and 87 - quite a career.