I don't know if there is a way to express to a parent faced with such a catastrophe... any way to express a perspective that they could possibly see over the blackness. I don't know that there is any point to try.
Presenting the flag "on behalf of a grateful nation" is the custom, but I doubt that any parent at graveside ever really even hears those words. Their world is collapsing in on them at that moment.
It is only from the distant view of history that justification ever makes any sense. Was D-Day worth it? Of course it was. Was it worthwhile to a recipient of the horrid telegram that day? There is nothing to be gained by asking.
I am personally distant from these losses so far. But I seek out these stories and these people because I need to know the pain of it. I support this effort, and I know there is a horrible cost, and it is precisely because I think we are doing right that I must at least see the whole cost of it.
Oh, I know. But we must win this. We need to be worty of these sacrifices, and I wish we could extend our gratitude and sympathy to these folks. I want them to know that we notice.