(a) Except as provided by Subsection (b), the medical power of attorney must be signed by the principal in the presence of two witnesses who qualify under Section 166.003, at least one of whom must be a witness who qualifies under Section 166.003(2). The witnesses must sign the document.
(b) The principal, in lieu of signing in the presence of the witnesses, may sign the medical power of attorney and have the signature acknowledged before a notary public.
(c) If the principal is physically unable to sign, another person may sign the medical power of attorney with the principal's name in the principal's presence and at the principal's express direction. The person may use a digital or electronic signature authorized under Section 166.011.