That is the choice he make. IMHO, he made the right choice by demonstrating that he didn't know the subject at the interview.

If I were him, I would do something similar but pointed out I refuse to answer in that way.

Of course, I have enough money, so maybe my perspective is different now. But you get the point, it's your choice, that would cascade into your rest of your actions in the future. What matters is now, not later.