Legal Question in Family Law in California

If the home was gifted by husband's parents to husband and wife, then there can be a community property claim.

I don't see a legal right, unless there are some facts that you are not telling us.

If title was never put in the name of H&W, remaining instead in parent's name, and H&W were only given a right to live there as long as parents let them, W has no rights to the house of any kind. Nor does H, for that matter, if he had a falling out with his parents.