Confused12345 said:
And did your friend have any trouble with immigration coming back? Did it take very long to go thru them?
You wait your turn in line, approach the officer, say "I'm a PR waiting on a renewed PR card", the officer swipes your passport, sees your PR status in the system, says "Welcome home" and sends you on your way.
It doesn't take any longer than if you had the card, as the card is not required to enter Canada. Last time my partner entered, the officer never even asked about the PR card because she saw my partner's status as soon as she swiped the passport.