I wouldn't say it's so much his fault that he didn't learn French growing up in Montreal; if he'd been exposed to the language from a young age, he'd have picked it up, as all young children without learning difficulties are able to.
So the fact that he didn't is more on his parents than him, they must have raised him/predisposed him to a monolingual environment.
As for learning the language by May, well, that's a tall task. Still, it's more than doable in three years. Having been completely self-taught, in 11 months I've gone from barely being able to ask someone's name to having a B2 certification; I can read French novels, watch films without subs, and hold everyday conversation. That's with less than a year of admittedly consistent learning, but I did it without a teacher and in my spare time.
Not that he's necessarily going to make the effort to do the same, and he'll need more than basic French to win.