I did the same thing, but in reverse (Canadian studying in the US). I did a few things to mitigate exchange rate risk.
1. Worked in the US and earned USD -- student visas allow you to work up to 20 hours a week on campus. I believe the Canadian international student visa offers the same benefit.
2. Got a scholarship, paid in USD.
3. Stayed on campus and worked in the summers, earning USD.
4. Exchanged from CAD and USD as necessary to cover the shortfall.
By earning as much in the currency that I'm spending in, it helps to mitigate currency exchange risk. I'd encourage your kid to do the same, plus it would help you out not to have to shell out so much for their education.