Legal Question in Wills and Trusts in California

What you are describing is "undue influence" and/or "Financial Elder Abuse". If someone changes a will or trust because of undue influence, those changes can be set aside. This can be difficult to prove and costly. If you feel that your parents cannot manage their own affairs, you may need to consider a conservatorship that would also potentially invalidate any recent changes to assets or estate planning documents. You should consult with an attorney as soon as possible regarding the specific facts in your situation.