Personally, I think the best thing to do is the here-and-now issues. Instead of trying to rewrite his knowledge of history, focus on the corruption and such going on now. Eventually, all on his own, he'll see the inconsistencies on his own. But whether he does or not is his business. Don't try to change him. Let him be himself.
"Moderation in temper is always a virtue; but moderation in principle is always a vice." -- Thomas Paine