From what I've been told, he does speak English well enough, but I'm not too sure how comfortable he is with the language.
Many Koreans are able to understand and write in English but have difficulty in speaking. It is the same for many of us leaning Korean. I may be able to read it and perhaps understand simple Korean, but ask me to speak Korean- I'll freeze.
He may just be shy in speaking it in front of a crowd. I don't know. Well, if he ever comes this way again, we can request him to speak a few words in English.