There's no body so no evidence that she died. It's more of a missing person, I think, with a high likelihood that she is dead.
If ANYTHING could possibly be worse than having your child die, it would be not ever knowing if the child was dead or alive. You would eventually have to give up thinking they were alive somewhere and resign yourself to believing they were dead but to never know anything would be torture. Jug Twitty lost his wife at the same time he lost his step daughter.