??? Capsize and sink do not mean the same thing. Odds are he still has possession of the boat. It's location wouldn't matter. HOWEVER, USCG ships are fitted with a GPS system called AIS. They could release the data, which would show if they were in Canadian waters.
Even tiny fishing boats use GPS these days. He probably has his own with its own metadata, unless he's too old school for that. Hell, his PHONE should have metadata proving he never crossed the border.
In an interview, he mentioned losing his phone when he capsized.