1. Before the PPR is sent IRCC will ensure that your medicals are valid not only when your application is approved, but also when you land and they you have sufficient time to land. If your medicals are expiring, IRCC will send your medicals for reassessment to the Regional medical officer who will make a determination on whether to extend them or ask for re-meds.
To know the details see the expiry date of your PR visa and COPR.
2. If you have received your cOPR, and you cannot land before the expiry of COPR, then you will have to inform IRCC, and seek an extension. IRCC will follow the same process as above and let you know if you need a re-med or not. You can do your meds without IRCC asking and submit the upfront sheet, but for most applicants IRCC is granting medical extensions.
Unfortunately, immigration is law and the law is provided in the Immigration and Refugee Protection Act and the Regulations, supplemented by the manuals. It is not a google search or what the IRCC website says and neither the info on the website can be quoted in the court. It is just to make information available to people so that they can understand.
See
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