On the other hand, it'll be a Canadian mental facility, provided under their interpretation of 'National Health,' so perhaps not so different than prison at all.
Hawkgirl, it would be a question for the judge here if the issue was his mental competence to stand trial, but a question for the jury if the issue was simply his sanity at the time of the offense. Canada starts from the same legal heritage, but does not necessarily track with US law, and certainly not with US individual rights.