As soon as the Succession debate is withdrawn, he asks his servants to arrange a meeting with Baron Pichot at his earliest convenience. (He doesn't expect to be kept waiting, unless the man has even less sense than he looks.)
Good.
"It is the custom of men in Axis to be honest with each other. I expect the same of you. I will pay for an Abadar's Truthtelling afterwards; I will expect you to confirm not only that you have not lied to me nor intentionally deceived me but that you have not withheld information of relevance. Do not waste my time by preventing yourself from being able to attest to that. Am I understood?"
None of that is actually complicated but for some reason mortals on Golarion keep having trouble with it.
So Antoni tells him.
He is well-practiced, by now, at considering only certain parts of the situation. His brother's lawless treachery comes to mind easily; his oath of obedience is safely beneath his mind's notice.
If that's a remotely accurate characterization of the situation, he absolutely does not want this man's older brother anywhere near power.
Unfortunately, he doesn't want this man anywhere near power either. If he had anyone at all to replace him with, it would be an easy decision, but finding anything resembling a qualified candidate is difficult, even when he lowers his standards far enough to account for the constraints of the Material.
"Tell me about your younger brother."
"He is still a child, Your Excellency, though a clever one. He spends most of his time being tutored in wizardry, and when he speaks of his ambitions nearly all of them are scholarly." He's almost certainly some sort of heretic, which is normally the sort of thought that passes by too quickly for magic to catch.
'Struggled to understand some of Iomedae's teachings' is clearly some sort of euphemism, but Maxim has no confidence he'll be able to guess what it's covering for. Given what he's seen of Chelish people who believe themselves to be correctly understanding Iomedae's teachings, he's rather concerned that it'll turn out the boy has a recreational torture hobby. He'll still speak to him after the convention, but he's not optimistic.
"Very well.
I have been given wide latitude to replace barons and minor lords within my territory. If everything you have told me is true, I fully intend to strip your elder brother of his titles. I have not decided whether I intend to do the same to you. Insofar as my decision will be influenced by this convention, it will not depend on whether your committee technically managed to pass a provision that can be read as disinheriting your brother, but on your own trustworthiness and competence. Am I understood?"