I will comment here:
First IDK how much he knows about Bitcoin, so intro is really short. Just tell him that Bitcoin is an economy based on a monetair medium(consisting of one trade asset/valuta) that gets created and validated by everyone. Instead of being relyant on 3rd parties(banks) to confirm validity or creation of the asset, you can do it yourself and noone can stop you from knowing the truth about an transaction. This is ideal properties for an economy that thrives on a honest signal. 

 Thanks for the elevator pitch! 🤙🏼

I think he might be further along than that …

Along with the books I’d like to help some helpful links or content … 

 What we need is a website to list all factors that bitcoin had to deal with. The social aspects and keeping it centralized. Soon he will come by the blocksize wars. Tell him that if they made the blocks bigger, it would grow to fast for many, centralizing the stuff. Nothing matters more then keeping the base layer decentralized.