you need to apply extension 30 days ahead for further stay. Ideally the officer at port should have stamped for 2 years , but looks like it was stamped for 1 year only..if visa expiry is April end , then quickly go and apply for extension. They can be here on implied status till IRCC reverts. They might ask for medical exam but am sure they will extend...
Thank you for your reply. There is no stamp/date for 2 years on the passport. It just has the stamp of the day they entered. Their visa is going to expire on April 23rd, so I'll apply for an extension today.