TS, I applaud your courage to sit through a 2 hr discussion like that. You're right, though, you never know where it might lead. It's like planting seeds.
This reminds me of a phone conversation I had 9 years ago. I called someone I thought was a long-time JW. Turns out she was out and "head over heels in love" with Jesus. It's a long story but the point is I did not hang up once I realized she was an xjw. I listened. I evaluated what she had to say and although I intellectually dismissed most of it at the time, seeds WERE planted.
I believe that experience helped me to consider/listen/evaluate what people much closer to me had to say when they started to have doubts about what the WT teaches. Today I see this org for what it is. God bless your efforts.
Skeptic1914