It's too bad indeed that the weather threw a wrench into his plans. What equipment does AC/Jazz use on their YHZ-YYZ route? It could possibly have different landing restrictions (eg: use less runway for a safer landing) than a 737. That might have been one of the reasons.
I wonder how could he have been re-routed on WS? Unless they would have sent him back to Toronto and then on to St. John's. Unfortunately, WS doesn't have Moncton/Charlottetown-St. John's flight.
At the end of the day, I'm glad to hear that he did get home safely and hopefully he can work out some sort of compensation with WS.