Legal Question in Real Estate Law in California

First, unless you already know, you'll need to find out if the house was in the trust at the time of the owner's death or not. If it were in the trust, the trustee would be the legal owner and the bequest would not be subject to probate. If the house were not in the trust, it would indeed, as you say, pass to the heir under the will, and would be subject to probate. In this latter case, there is another possibility, and that is that the will gave the property to the trustee to hold for the eventual heir.

In any of these three cases, the "person" (to use your word) can leave his or her interest to his or her spouse, The only difference is whether the interest would be legal ownership or beneficial ownership.

Remember, trustees own trust property, but they are subject to strict rules requiring the trustee(s) to follow the terms of the trust instrument and hold and manage the trust property for the benefit of the trust beneficiaries.

This is a real estate lawyer's answer. If you would like further, clearer and better explanation, either re-ask your question under a "wills, trusts and estates" type of heading on LawGuru, or if a probate is involved here, ask the attorney handling the probate. Obtain and read a copy of any trust affecting this house. Finally, the person and the spouse should retain their own estate-planning lawyer and set up their own estate plans.

I cannot answer this question without knowing the terms of any will, trust, and how title to the property was held.