I have a friend that came to Canada on a Canadian B1(visitor-business) Visa 1 month ago. He could normally stay over for a period of 6 months from his date of entry, but his Visa will expire in 2 weeks from now, and he was planning to stay another 2 months. So the question is: Does he need to leave in 2 weeks when his Visa expires or could he stay up to the maximum time allowed from his date of entry in Canada regardless of the upcoming Visa expiration date?