No words for us...

I read 'My Sister's Keeper' a few days back. It has a very unexpected ending to say the least, but there was something in those final pages that rang a bell inside of me. I'm not sure why, but I explained it to LO. Our conversation went like this:
Me: You know that in the English language there is a word for children who have lost their parents...
LO: "Orphans?"
Me:"Yes, orphans." "There is also a word for people who have lost their husband or wife.."
LO: "What's that word momma?"
Me: "Widow or widower."
Me: "There is no word for people who have lost their children."
LO: "Is there a word for people who have lost their brother or sister?"
Me: "Nope."
Lo: "But why not?"
Me: "I believe, that there are no words for us, because no one would want to say them."
"They would be the saddest words you could ever say..."