It says on the site that all e-mail responses will be slow, as e-mails must be be physically printed out and mailed to him. So, it sounds to me like someone made the website for him, and he just sent them a letter saying what to say. Charles Manson had a
website up at one time, too, via the same methods (outside help).
Unless you prevent him from sending letters or having visitors, I don't see how you can stop this.