The property Dad owned during his life became property of his probate estate at his death, and control of that property will be the responsibility of the personal representative2 of that estate when s/he is appointed . . . unless . . .
Unless the property at issue was jointly owned with someone else, and the nature of the joint ownership provided for that property to pass at his death to that joint owner; or
Unless the property is subject to a beneficiary designation of some sort (such as a life insurance policy, retirement account, life estate, or payable on death account), in which case the property passed at Dad’s death to that/those designated beneficiary(ies); or
Unless, at the time of death the property was held in trust, in which case the Trustee of the Trust is in control of the property.
While the personal representative will not have legal authority over the property until his/her appointment, Michigan law does provide a person who later becomes personal representative with some authority to act prior to appointment.
Which leads to the question of: who will be the personal representative? The answer in most cases is the person nominated to be personal representative in Dad’s will. If Dad had no will, Michigan law provides for a priority for appointment: surviving spouse, adult children, etc…
Clearly, someone who had “power of attorney” over Dad while he was alive can no longer rely on that document for authority to take any action with respect to Dad’s property after Dad is deceased.
2The term “personal representative” is what Michigan law uses to identify the person who administers a probate estate. People often use the terms “executor” or “administrator” to mean the same thing.