For +CHF1000 per head, for a once-in-a-lifetime experience, I'd probably do it.
As others have said, the ZRH-YUL flight is the shortest transatlantic flight and Business Class is definitely perfectly acceptable. Nobody "needs" F, especially not on a flight this lenght.
But if you have never experienced the luxury and pampering of International First Class, including the new ZRH lounges (and possibly the new B777, which I think operates to YUL on a few days this spring) it could be a worthwhile treat. Especially if your father pays.
