I realized that some forum members ask questions that they already know the answers.
1- Your parents come as visitors.... A visitor is NOT eligible for OHIP.
2- They will be eligible when they become officially PR and their 3 months waiting period will START at day 1 after they sign for OHIP after PR status granted. In this case no OHIP without PR status. As long as your parents status remain visitor, they are not eligible and 3 months period couldn't apply.
Thanks.
Ok thanks