Prob. Code, § 4674

If the written advance health care directive is signed by witnesses, as provided in Section 4673, the following requirements shall be satisfied:

(a) The witnesses shall be adults.

(b) Each witness signing the advance directive shall witness either the signing of the advance directive by the patient or the patient’s acknowledgment of the signature or the advance directive.

(c) None of the following persons may act as a witness:

(1) The patient’s health care provider or an employee of the patient’s health care provider.

(2) The operator or an employee of a community care facility.

(3) The operator or an employee of a residential care facility for the elderly.

(4) The agent, where the advance directive is a power of attorney for health care.

(d) Each witness shall make the following declaration in substance:

“I declare under penalty of perjury under the laws of California (1) that the individual who signed or acknowledged this advance health care directive is personally known to me, or that the individual’s identity was proven to me by convincing evidence, (2) that the individual signed or acknowledged this advance directive in my presence, (3) that the individual appears to be of sound mind and under no duress, fraud, or undue influence, (4) that I am not a person appointed as agent by this advance directive, and (5) that I am not the individual’s health care provider, an employee of the individual’s health care provider, the operator of a community care facility, an employee of an operator of a community care facility, the operator of a residential care facility for the elderly, nor an employee of an operator of a residential care facility for the elderly.”

(e) At least one of the witnesses shall be an individual who is neither related to the patient by blood, marriage, or adoption, nor entitled to any portion of the patient’s estate upon the patient’s death under a will existing when the advance directive is executed or by operation of law then existing.

(f) The witness satisfying the requirement of subdivision (e) shall also sign the following declaration in substance:

“I further declare under penalty of perjury under the laws of California that I am not related to the individual executing this advance health care directive by blood, marriage, or adoption, and, to the best of my knowledge, I am not entitled to any part of the individual’s estate upon his or her death under a will now existing or by operation of law.”

(g) The provisions of this section applicable to witnesses do not apply to a notary public before whom an advance health care directive is acknowledged.