Section 5-301
(a) A parent, by will or other writing signed by the parent and attested by at least 2 witnesses, may nominate a guardian for an unmarried adult child who the parent believes is an incapacitated person, may revoke or amend the nomination, and may specify any desired limitations on the powers to be granted to the guardian.
(b) An individual by will or other writing signed by the individual and attested by at least 2 witnesses, may nominate a guardian for his spouse who the individual believes is an incapacitated person, may revoke or amend the nomination, and may specify any desired limitations on the powers to be granted to the guardian.