What's his opinion of 9/11?
If he thinks the official story is true, then here would be a good place to start in chiselling through those walls of mainstream deceit and lies. I've seen 9/11 work as a catalyst before, but it's a hard path. As Mark Twain said, "It's easier to fool people than to convince them that they have been fooled."
For a video that encapsulates it all, this is one of the best. It's long though, but necessarily so. It's very thorough, and never boring. And it doesn't ram outlandish conspiracy theories down your throat, it merely shows/tells/underlines what is wrong with the official story, all its discrepancies, inconsistencies, and downright lies. It tasks you to join the dots yourself. Once he starts to join those dots and ask those questions..mission accomplished.