In this case it would help to know what kind of books you already suggested to your economist friend and what he did not like about them. When economists say they want something "highly readable," I wonder how seriously they intend to take it. If the questions to understand are actually complex and sometimes difficult, why should an economist not have to study hard (like the rest of us) to understand them? 
We could argue, the history of economic thought is much harder than economics. 
Anyway, how seriously would an economist take a historian who asked for some easy economics?