If he gave reasonable answers when pressed, despite being initially resistant, it sounds like the interview didn't give any insight into whether he was a good employee or not.
It certainly did! I just didn't understand at the time not to hire employees who simply say "I'd Google it" over and over :D.
How about stack overflow?
Ah, so was the candidate poor because they had a bad attitude and refused to try to solve the problem at first, or was it because their technical skills were lacking?
More the former. Technically they seemed quite proficient, but they proved difficult to work with and didn't end up gelling with the team very well.