Here is a copy of the act. Who and what is subject to the act and the duties of the Commissioner.The complaints are outside his mandate. The Queen's prerogative is not subject to the OL Act. And any recommendations made by PCO to the PM would constitute advice to the Minister and are thus confidences that would not be disclosed to an investigator.
He's either wildly ignorant about Canadian constitutional law, or a performative buffoon seeking attention.
As far as I can see, the office of the GG is subject to that act. There is a list of exempted institutions like the Senate or HofC for example.