You have been misinformed. Health card is not related to the CoPR expiry in Ontario. OHIP ( Ontario health card) card has a validity of approx 5 years and can be applied with CoPR, address proof, and identity proof. No need to wait for PR card.Someone mentioned that their health card got extended only till the COPR expiry. So, it may be a good idea to extend the health card after receiving the PR Card. All the expired health cards are extended by the province (ON) until further notice anyways.
https://www.ontario.ca/page/health-card-renewal