Are Brady and Matthew related to Walter Tkaczuk, the great NY Ranger center of the 70s?
Not related and the last names are spelled slightly different.
Their father is Keith Tkachuk who was a long-time player in the NHL. Last year when the NHL had the 4-nation tournament, at the Allstar Game, when the US and Canada played in the finals, 3 fights broke out in the first 9 seconds of the game, the first two fights involved Mathew and Brady Tkachuk, each fighting a player from Canada.