There is no law against smoking crack in Canada. It’s illegal to possess it, but not to smoke it (I know, I don’t entirely get it either).
There is no point in discussing criminal charges, this is all about his credibility as a mayor. He had plenty of opportunity to say, “If someone has a video of me smoking something from a glass pipe, it was not crack I was smoking” months ago. Instead he said, “I can’t comment on a video that may not exist.”