Your mother should establish an entire estate plan which may include a will, financial power of attorney, medical power of attorney, advance directive, and disposition instructions. It may also be beneficial to provide a trust based estate plan to avoid probate.
I would strongly recommend that she retain an estate attorney. This is especially important if there are capacity issues or she is close to passing. If getting an attorney is not possible or feasible, at least get a credible book such as those available through Nolo publishing.
DISCLAIMER—This answer is for informational purposes only and discusses legal principles, trends, and considerations and is not intended to be used as specific legal advice in any way, shape or form. This answer does not establish an attorney client relationship. For legal advice, you should obtain legal counsel in your jurisdiction for advice regarding your unique circumstances.