You did really well! The hard part is getting past all the WT programming. If you are going to get through to a JW, you usually have to ask the questions they would never ask because all they do is repeat the WT mantras.
Note all the things your friend said that could have been written by the GB:
“Well, this is an organization of imperfect people, and didn’t the disciples in the first century have wrong expectations?” “We are trying to stay alert and fit the puzzle of current events to the bible prophesies that we know are related to the time of the end.” (He doesn't see how different this is than, "We are in the truth!")
"Well, you wouldn’t want to be part of Babylon the great would you joining the YMCA?” (Missing the point completely and invoking the bogeyman "Babylon the Great"...)
He asked who I felt God was using. (Typical WT question. It assumes God is using one and only one organization.)
“What about the preaching of the good news, who’s doing that?" (Assumes the WT news is the good news of the Bible despite the fact that "the truth" keeps changing).
He asked me if the end did come what I thought Jehovah would do with me and my family. (The last line of defense. "If you don't obey the GB, you'll be wiped out at Armageddon. I think you did very well. Your comments really pointed out that the WT has supplanted Jesus. They think that no one can be saved except through the GB...)