Of course they're going to grant him immunity. Of course they are, because this world we are in has become a Byzantine labyrinth of unlikely outcomes. We need to be thinking about a strong resistance.
They're not going to actually grant him immunity. They're just going to invent a 7-part historically grounded test based in the Federalist papers, Ovid's poetry, and the moon's gravitational pull that will be subject to various other stalling options just to stop the trials from going forward.