It's good to be prepared, to plan out what you're going to say. Writing it down to help your thought process is great.

Actually using them is probably not - I'm going with "realistic" - conversations tend to have unexpected turns.

Not to mention the awkward nature of the execution of the idea.

Listening is going to be key here, not fumbling around with the card for the next thing you want to say.

I'd say tell him to focus on listening. Don't treat it as a debate.