Does this mean that for the last 13 weeks they've been one week ahead, or something else?
How much does the CEO's advances affect your 8 weeks of runway? In addressing this situation, I'd be mindful of the fact that the company won't exist if you run out of runway spending all your time on this issue. It's a frustrating situation, but legal bills can eat up runway pretty fast. The best possible outcome is to get some lawyer friends to help you figure out a slam-dunk case and get the CEO out without protest. But IMO (as a founder and former SV lawyer), this is pretty unlikely.