I understand that the way to help a witness is to present him or her with information or facts that will get him or her thinking. I understand that heavy use of the Bible or discussions to prove them wrong lead to nothing, because people go into their "I-won't-listen-to-you, Satan" mode and, also, because subconsciously they realize they have been duped and refuse to accept they were so gullible.
With regard to the internet, I think you can talk about the good things it does offer to people. For example, free software, communication, information. You can tell him that, yes, there are many bad things out there, but, in general, the internet is a good thing if you exercise your critical thinking. I think this is an indirect way to expose him to information and suggest that critical thinking is not a bad thing.
I hope this helps.