Legal Question in Real Estate Law in California

I can't give you a really specific answer without knowing how the real estate investments are structured and how title is held, but in general, the debt associated with real property (tax liens, deeds of trust, etc.) will pass along with title to the heir. I would advise trying to do whatever advance planning is possible now, but be sure to rely upon advice of professionals (real estate and estate-planning attorney) before making any changes in the status quo for either of you. In a worst-case scenario, you could probably avoid the liabilities associated with an overburdened property by declining to accept it as an inheritance.

Her estate would be subject to any debts. You would not be personally liable unless you take some item of her estate without satisfying the debts, or sign a guarantee for the debts.