Your spouse should take his OWP to Service Canada so that he can be issued a SIN number.
However, just having the OWP and a SIN number is not enough to be eligible for OHIP. Your spouse will need to find a full-time job. He will then need to bring a letter from his employer stating that he is employed full-time and that they plan to employ him for at least 6 months. This letter is what makes him eligible to apply for OHIP.