I have to disagree with you. Encouraging him to get these common coins certified just plays into his delusion. He will simply end up losing his fees for grading/authentication.
With the next newbie we could play along with his/her game. Hey, that is one heck of a coin, I will pay $5K if it comes back like you think it might. Here is a submission form, I recommend "Walkthrough" service or even "HIgh Value Walkthrough" to get maximum potential grade. Credit card please.... I was in a shop today where the guy swears they switched coins on him so he will not submit anymore. He showed me a 1926-s Buffalo nickel he says was MS65 plus, but when he sent it to be graded it came back having been lasered and body-bagged by them. And he was 100% sure, because he says he had bought it 40 years ago before they even had lasers. The stories and suppositions never end...
That mentality doesn't stop at coins, there are plenty of people who like to believe particular items they may possess are priceless when they're really not. My dad had this problem. He'd spew out prices on things he thought were worth money when they could be found for a fraction of the price you could find at local shops or online, etc. Father: "That there is worth $100." Me: "I saw it for sale at a local store for $5 though, how can it be worth $100?" :yes: