Kogan, to the extent you are still looking for advice for the situation you describe, let me provide you with my two bits:
Bit 1: Get a lawyer. IIAL. This is an unfortunate necessity when someone you're in conflict with retains a lawyer. The U.S. legal system is complex and based upon rules that have been building on each other literally since before the founding of this country. A good lawyer will know how to exploit this complexity in their client's favor. You need the same expertise, at a minimum, in order to avoid falling into any common traps. Imagine that you and the person you're in conflict knew nothing about DF and agreed to resolve your dispute by playing a game to see who could last longer. Imagine the advantage if one side had a Bay12er on their side. Our legal system may not be as complex, but I doubt it is any more intuitive than DF, and you need someone to summarize the equivalent of dwarven hydrodynamics for you.
Bit 2: Do everything you can to keep the lawyers out. Family lawyers don't solve problems. They help clean up as much as possible when there is no solution. The only way to really fix problems with personal relationships is to take responsibility for doing whatever it takes to fix it yourself. This will likely mean doing a lot of things you don't want to do, and will certainly be unpleasant. Be conciliatory even when you don't want to be. Listen to people quietly when they're being completely unreasonable. Recognize their point of view, demonstrate that to them, and then communicate your position calmly, quietly and reasonably even if your blood pressure is through the roof. In the end, if you're going to court you've already lost, no matter how good your case or how great a lawyer you have.