Declaring an emergency due to the unexpected headwinds is exactly what he should have done. The quarantine would almost certainly have not been the case if it was simply a matter of refueling the airplane and being on his way without leaving the ramp (for anything more than to use the washroom and pay for the fuel). Most likely he would have been asked to take a COVID test on reaching his final destination and report the results back to the Canadian Border Services Agency for potential contact tracing purposes. And all of that would have been done over the phone with CBSA since they don't have anyone close by except at Vancouver International these days. Forcing him to quarantine for 14 days after declaring an emergency would have resulted in the inevitable contact with more Canadians over a longer duration than a ramp stop to refuel, so there's very little chance they would have detained him, unless there was reason to believe he was infected. I'm also wondering why he didn't stay closer to the mainland, overfly the Fraser delta and land at Bellingham instead. It's not like there's a whole bunch of commercial air traffic congestion around CYVR at the moment. Or even cut over to Friday Harbour in the San Juan's which is further north than where he went down.