Well I was with her but landing at Pearson and the entire process probably took about 45 minutes or so. Stood in line at the customs desk, then they sent us to a room where the immigration officer processed the COPR and marked additional information i.e. landing date, etc. We got our luggage after that and they didn't even bother us checking what was in the luggage. I was fully prepared with a list of all her belonging and pictures of valuable items such as engagement ring, and other expensive jewelry, but they just waived us through to exit. I was a bit disappointed since I had worked so hard on the list, and photos. I actually asked the officer... are you sure you don't want to check? He just laughed and said, no don't worry, just go through. hahaha
So yeah don't worry I'm sure he won't miss the flight... then again he is in Canada there are flights every hour or so in the worst case scenario he will be a bit late in the reunion.
Just kidding!!!! I know every moment apart is already too long.
But yeah the SIN number can also be obtained at any Service Canada. So in the event where time is a factor, don't worry about it too much.
Have you bought medical insurance for him, just in case, since he is not covered under OHIP for 3 months?