Legal Question in Wills and Trusts in California

You can have your mother execute a form power of attorney (available through the legal forms tab, above). If she is unable to comprehend what's going on, you might have to petition the court in the county in which she lives to be appointed as her conservator. By the way, there are two types of powers of attorney and conservators -- one for health care (the living will/conservator of the person), and one for financial affairs (conservator of the estate).

If your mother is already too sick to make decisions, it is too late to get a power of attorney. A power of attorney must be given by someone when they are completely competent to act on their own, and unless it is a "durable" power of attorney, it expires when they are no longer competent. It sounds like you will need to apply for a conservatorship. You will need the help of an attorney for that.