Legal Question in Criminal Law in California

You can't of course.

She can if she is not also a 'prohibited person' -- that is, any person who has been convicted of a felony, certain misdemeanors, certain firearms offenses, who is addicted to narcotics, who is the subject of a domestic violence restraining order, or has been committed to a mental institution.

HOWEVER, For a felon or anyone otherwise prohibited from possessing guns under federal or state law, it is a serious risk for him living in a house where there is a gun. He can not even be in the presence of firearms or ammunition without risk of being accused of a felony. I have for years been warning that for both parties to be as safe as possible from legal problems when a felon or other prohibited person is present in a house [resides or visits], a gun owner must secure all guns and ammo in a locked gun safe, preferably in a locked room to neither of which a prohibited person has access. Knowingly allowing the prohibited person apparent access to firearms could result in the gun owner being charged with ‘aiding and abetting’.