A general idea could be to get your son to participate in a local university, if it is a good one, or take him to events/summer programs in a top university in

A general idea could be to get your son to participate in a local university, if it is a good one, or take him to events/summer programs in a top university in another province for a few months each year. Since your son is likely very good with English already, it might not be necessary for him to continue studying in an international school (I understand there are trade-offs). It might be worth it if he moves to a top local school, where more high achievers study instead. For something more specific, I think I might be of some help. Please send me an email (in my profile) if you'd like.