A child in Canada is in a terrible car wreck. All family members die, his parents wrote no will, and he is left in a coma. What happens to him and who pays medical bills/holds custody of him?

Can the hospital decide to pull the plug or not? Or is there some major legal mumbo-jumbo that prevents them from doing so? Who makes the decisions about him?
Also, could a complete stranger/charity organization apply to sponsor this kid and pay for his medical bills so he isn’t taken off of life support? Could a stranger apply to ADOPT this kid in order to do so?