Legal Question in Real Estate Law in California

Yes, through a partition suit [that can cost $10-15,000]; the court will divide the assets which normally requires the sale of the house.

Yes, it is called a partition action. It is much like a partnership dissolution case. How much it costs depends on how much the parties want to fight about it before they face the fact that they just have to make a deal, sell the house and divide the proceeds.

Yes. In modern times, a "partition" action almost always requires sale of the property and dividing the net proceeds, although in earlier times, partition was done by physical subdivision of the property. When there is no net equity, the plaintiff (usually) gets stuck with the costs and legal fees, and the lender gets the selling price and eats the shortfall.

If there is equity, the court will hear evidence as to whether it should be divided in accordance with the former owners' interests (often, 50-50) or whether one or the other former owners is entitled to more based upon a disproportionale contribution to joint costs such as mortgage payments, insurance, property taxes, and certain essential repairs.

Many partition suits settle out-of-court when the defendant(s) see the inevitable resuth and agree to sell without being pressured.