Did you both come to an agreement that it was the Catholic Church that compiled the Bible? If so, how could he possibly argue that it contradicts Catholic doctrine? It would be silly, at the very least.
The problem anyway would be the assumption that the Bible simply fell from the sky. Clearly, the faith must have preexisted the Bible, because otherwise how do we decide what is proper scripture and what is Gnostic nonsense? And if the faith preexisted the Bible, wouldn’t it make logical sense that there would be elements of the faith not possibly written down in the New Testament? After all, the Bible isn’t an instruction manual on how the faith works. Most of the New Testament is composed of letters by apostles to other apostles or churches, regarding specific issues. Wouldn’t make sense that they’d cover everything there is to know about Christianity in them.