In Illinois, a comprehensive Advance Directive requires the completion of two separate forms. The first is a Living Will, while the second is a Health Care Power of Attorney (a.k.a. Health Care Proxy).

Required Details for the Last Will and Testament To be legitimate, your IL Living Will must be signed by you and two (2) witnesses.

(Via Ilinois Department of Public Health)

Required Information for naming a Health Care Proxy:
For your IL Health Care Proxy form to be considered genuine, you and two (2) witnesses must sign it. Witnesses CAN NOT be:

• An attending physician, a provider of mental health services, or a relative of the physician or provider.
• An owner, operator, or relative of an owner or operator of the healthcare facility you are a patient or resident of.
• A parent, sibling, descendant, or spouse of a parent, sibling, or descendant of either the patient or any agent or successor agent under the preceding power of attorney, regardless of whether the relationship is via blood, marriage, or adoption.