We are Catholic, with the mark that we are obedient to our teacher(s), and do not “discover” the truth of Scripture by our hard work and native brilliance. We instead believe our Teacher’s explanation of the Scripture and of reality.
Protestants must do their own interpretation of Scripture because they need to counter what is Catholic, just as Simon Peter tried to turn Jesus away from Jerusalem, but instead he heard the Master say, “Get BEHIND me, you satan; if anyone will follow BEHIND me he must deny himself, deny his own desires for what the Scriptures say, and let me interpret the Scriptures as will be done on the Road to Emmaus for two of my followers.”
Your friend already gave up his following behind his Teacher when he abandoned the Magisterium and Catholic Scholarship to find a “more desirable” interpretation or understanding. Patristic Theology would not have taught him the same conclusions he has reached, but he was somehow won over to a false understanding of the place of historical-critical methods of viewing scripture, as if the meaning of Scripture were in the hands of scholars.
But Scripture is the composition and property of the People of God, under the teaching authority appointed by Christ - Apostolic Authority / Succession. It is a governing council that named what is Scripture with councils and magisterial and papal declarations of interpretations.
Our Church is about believing a Word delivered by a person, in person, from a person you trust, who is relaying it to you in your generation. We do not “believe the Old Testament” because we have analyzed it, but we analyze it because we believe our Teacher, who opened its meaning to us. Words can mean many things, but only the Teacher’s interpretation is correct, (because He is actually the author of it). We have the Teacher’s interpretation because we have the Teacher’s line of faithful students and servants teaching us today what they received to pass on to us.
John Martin