As you've said, if he's 15 he's a minor. In Canadian law, minors are the wards of their parents. There are two parents involved here, a mother and a father. The mother is partially responsible for him. I don't know why you wish to ignore her role and responsibility in acting to protect her son from jihadist incitement, the quest for martyrdom, and wanting to get engaged with al-Qaeda, a known terrorist entity.
On May 27th, 2008. See this statement in context.