Most rigorous studies show that immigration is to the net financial benefit of a nation but the increase of foreign students in Canada is really just a story of capitalist greed. The quality of education is far too low for the cost of tuition and I'd argue its an extremist capitalist position to expect infinite growth from a nations productivity and to see decreasing fertility as an existential threat.
Now it's complicated in Canada because social services are funded by the current tax payer base and Boomers are about to decimate the healthcare system as they get older and sicker. But bringing folks over on false pretenses is not the solution to that.