I think about the only way McCain could actually learn, that is, to listen to someone else, would be if somehow he was associated with some offense against Islam. Nothing quite stimulates the intellect like an angry mob calling on you in particular to be beheaded.
“Oh, by the way, senator, there is an angry mob of ‘moderates’ outside that are calling for your murder.”
All it would take is some anonymous poster on a jihadi forum to say that they had observed McCain desecrating a Koran. No explanation, no evidence required.
The North Vietnamese proved how you could get McCain to listen. They also knew how to make him talk.