Come on mate be fair. The genocide was hidden. Was it implicit yes but it was ignored. Or They couldn't get their heads around it. Who could. The scope was utterly terrifying.
I am being fair, but I disagree with your assumption that the holocaust was something that was overly hidden from all but a select few of Germans.
Did everyone know? No. Did they have a full understanding? Perhaps not, but the numbers of Germans involved in the process suggests more would have known.
I did a paper on this very topic as part of my Masters, well it was the involvement of the Reichsbahn in the Holocaust, and their involvement was hugely significant.
It's not the right place to discuss about this now, but there is a multitude of evidence that highlights how many people were involved in the process over many years.
Then, you suspect their families would have known to some extent because people don't keep things entirely to themselves.