I've been wondering about this for a while. What do you say to the family and friends of children who die in tragic circumstances?

The idea of an afterlife, although absurd, offers comfort in such terrible circumstances even though it's false comfort. 
If someone dies in old age, or doing something in their life that they love, the question isn't so difficult.
They lived their life and that made them lucky. They got to experience the wonders of existence.
But in cases of tragedy, especially involving the very young, this just doesn't cut it. 
I don't mean to ask about the merits/demerits of the comfort that is found in false belief. 
Rather, how do we humanists best offer comfort during tragedy?