I had an argument with one on a song video. Every time I pointed out a flaw in his argument, he'd say that it didn't apply because the NWO knew we wouldn't believe him. For example, he said the NWO kills everyone who mentions it. I pointed out he was alive, and he said it was because nobody believed him.
You should have told him that you believed him.
Pretty standard protocol for any super-secret organization, cult, and etc. to take refuge in audacity, seeing as the more ridiculous the claims (which would be fact if the theorist was telling the truth), the less likely anyone would believe them; despite reality being pretty unrealistic these days. Best course of action: Don't do a damn thing.
Better to be assumed an idiot, than to speak up and relieve all doubt; or in conspiracy case, Better to be assumed as an evil bastard pulling the strings, than to retaliate and relieve all doubt (in the rare case that they botch a coverup; plus, psychological terrorism is far more effective than outright killing someone).
EDIT:
All that in mind, now that I come and think about it, that makes just as much of a counter-attack from the CTs perspective as well. CTs stop talking, silence themselves, and pretend to obey (or legitimately do so; and no secret messaging/ciphers and etc.), then the source of said theories can/will eventually make a mistake, and the CTs don't need to speak to reveal the truth. The conspirators' own paranoia of their people, and those who speak up suddenly gone silent and obedient will make them screw up somewhere down the line (Evil Villainy 101; never trust as good thing that comes your way, not even a pretty face. In essence, 50-50 is the safety zone.).
On that note, NSA, what's your opinion on my thoughts? Oh, and my cats enjoy playing with the lasers, so they're my security and head's up for your response.