Mich. Comp. Laws § 700.5308: Termination of guardian's authority and responsibility.

Sec. 5308.

The guardian's authority and responsibility for a legally incapacitated individual terminates upon the death of the guardian or ward, upon the determination of incapacity of the guardian, or upon removal or resignation as provided in section 5310. Testamentary appointment of a guardian under an unprobated will or a will informally probated under article III terminates if the will is later denied probate in a formal testacy proceeding.