If they are EU residents, then EU261 should apply and they are entitled to up to EUR 1,300 each in compensation for delayed bags. I received around 1,200 EUR from LH for delayed bags. Credit card claim might be easier given how AC treats EU261 claims. However, as EU residents they can usually access a mediation service to force AC to respond.

Have they called into the baggage claim line? I do find that AC doesn't always update the website and a phone call can usually get someone to update the website or find the bags sitting somewhere (hopefully Vancouver)