Legal Question in Real Estate Law in California

There is no simple answer to that question. It depends on way too many details of how title was and is held, whether it was in a trust or passed by will, who the trustee and/or executor is/are, whether record title to the property has been transferred, etc.

I agree with Mr. McCormick that all these issues may or will arise. However, there is a basic legal principle that co-ownership of property depends upon continuing mutual consent to the arrangement, and that when one co-owner "wants out," he or she is legally enabled to sue to terminate the co-ownership. This is done by a special kind of lawsuit called a "partition action," in which the plaintiff asks a court either to (a) split the property between the two owners (hence the name "partition"); or more often in modern times (b) order the property sold and the net proceeds of sale to be divided between the former owners in proportion to their interests.

In the case of inherited property, if there is a trustee or executor (your sister?), the process may be even simpler, but will depend upon the terms of the will or trust as well as applicable probate law.

If your mother passed away recently, or maybe even not so recently, the question would arise whether an attorney was retained to handle the estate. If so, I'd suggest asking him or her what your sister's authority (if any) stems from, or if she is just expressing an intent to go for a partition.

Any owner can compel a sale and distribution of proceeds by filing a lawsuit, unless prevented by the terms of a trust or something similar.. Consult with local counsel if you can't work it out among yourselves.