Ask HN: My Cofounder was diagnosed with cancer, what should I do?

My cofounder and I started the company 9 months ago. We are on 4 year 1 cliff vesting schedule. This coming June 2024, we'll finish the 1 year cliff. However he only commited 6 months out of this 1 year. And I can't blame him for that as none of us has expected this scenario. What should I do?