Mdlevine – very wise words, indeed. I recently went to a shiva house that was especially uncomfortable because the aveilim were two brothers (I am close friends with one of the brothers and his wife), and when my husband and I went to visit, they literally just stared at us silently and even smiled nervously, but both refrained from making any kind of a pischon peh to which we could respons. Thus we sat for several minutes, no one saying a word.
I later found out that our friend was just very flustered about how to conduct himself, and even though he knew he had to be the one to speak first, he just didn’t do it. Eventually someone did speak, but it was very awkward. We also did not know the nifteres, so we had nothing to say about her. I just said something like, I know she must have been a very special person to have produced such wonderful sons as our friend and his brother, and that we didn’t need to knwo her personally to see that. They actually liked that very much. There were no other visitors at the time, so we didn’t leave for a while, but as I said it was a bit awkward. Still, you have to always take your cues from the aveilim. And in my world, an aveil can talk to me anytime anyplace, if that person feels the need to vent about their loved one, even more so after the shiva. When everyone has gone back to his life and the aveil is no longer seeing a steady stream of people coming and going, that is the moment when they truly begin to feel the loss, IMO.