I guess you purchased the website at least that's how I interpret your information.
And no FTP is not enough in most cases to setup a website, you need to setup mysql, fiddle with phpmyadmin etc
Like mineistaken are pointing out, get him to send over the websites mysql files and you could import them yourself. Otherwise I don't see why he would need cpanel acces other than actually helping you out.
Brian, can you create database and import mysql on your own ?