Well, since her family and friends speak English, there's no reason for her to want him to learn it. Also, there's no reason for her to want him to learn it if they're not going to be together for a long time (see my reply regarding culture).

The only reason she should want him to learn it, at this point, is that it would be a nice thing for him to do--an expensive and time-consuming thing. I think that's a lot to ask, for a relationship of the one he describes.