Legal Question in Wills and Trusts in California

My condolences on the recent loss of your mother. Unfortunately, there is not enough information to give a quick answer. You say she left you and your brother her 1/2 of the residence. Was this by will? By the terms of a trust? Or by the manner in which title is held? Have you been placed on title? As for protecting your Dad, he may need a conservatorship at some point if his dementia worsens. Your mother was free to leave her share of the community property to someone other than your Dad, but if she had a will and left him off of her will, that could raise legal issues. You should really meet with an attorney who can review all of the documentation with you.