If you do want to read his dialogue, then you best reload after speaking with him. It's the safest thing to do currently. Your conversation does not have much of an impact on your latter encounters other than a few flavor lines, so it shouldn't be a big deal. It's the teleporting that despawns him permanently, and his dialogue ends with him doing just that (unless you initate combat). Again, as long as he doesn't teleport, he'll be at the start of DC. You are free to speak with him in the Oculus, though, but once you enter the Institute, he'll no longer be back there.
