Nobody will - because people don't usually want to buy it, unless they're going to use it. Family law is generally considered the 'dregs' of the legal profession. No one is ever happy with the results, and no one ever wants to settle - so that incurrs MAJOR legal expenses.
You can't sell a policy for $250 and pay out $25,000 to more than 50% of the people. There isn't any "risk sharing".
You should, of course, file a complaint with the state bar association. They will investigate and impose discipline where necessary. However, that doesn't really address your problem.
You probably lost rights to some monetary damages in the case he was handling. Some attorneys advertise that they sue other attorneys. Start with them. Most attorneys won't take a case against another attorney.
You need to act quickly. The attorney most likely has malpractice coverage, and any attorney you hire will make a demand against the insurance immediately. But they have to know about the claim. If your claim is good enough, chances are that the insurance company will want to settle quickly.
Attorneys don't do well as defendants in front of juries. Imagine that.
** Note: This is a general discussion of the subject matter of your question and not legal advice. Local laws or your particular situation may change the general rules. For a specific answer to your question you should consult legal counsel with whom you can discuss all the facts of your case. Answering this question does not indicate an attorney-client relationship. **