"Sad for the family's not knowing after all this time."
I've spent some time thinking about what I would do (and what I would think) in such tragic circumstances, and concluded that I would, with deep regret, mark the question down as 'known' after about 36-48 hours. The act of 'holding out hope' beyond the point of reasonability seems to do infinitely more harm than good.
What's missing is 'closure', but that's very different than "not knowing". Yes, it's a subtle point.