Please help with co-founder leaving before cliff

I publish illustrative scenarios prepared by my practice. All participants and conversations are fictional. The fictional posts are not posts by real users, accounts of client experiences, or reports of actual results.
Illustrative scenario prepared by my practice.
For informational purposes only. This is not legal advice. Laws vary by jurisdiction. Consult a qualified attorney for advice specific to your situation.
Hypothetical question

I'm in a difficult situation and trying to figure out my next steps.

co-founder leaving before cliff. I've been dealing with this for about 4 weeks now and the situation isn't improving.

I have already consulted briefly with a lawyer but the other party is not cooperating.

What's the typical outcome in situations like this?