I don't think he had any special responsibilities other then translating when needed. I remember reading in one of Johnny's old journals that once when he was skating in Russia, he was asked to help with a sightseeing tour as he was the only American there who spoke Russian. As to why he was the leader, I'm guessing it was due to his age or the fact that he's skated in Russia many times and is familiar with the customs etc.

****Keeper of Johnny's friendly rivalry with Evan****