Hemera didn't know the child existed until she rematerialized and Aether let her know.
Stella sometimes seemed more ghost than child: she would disappear for hours and reappear where she had no business being.
She was utterly mortal, except for her occasional habit of prescience, her blinding smile and constant, bone-deep calm, and the fact that one day she simply disappeared forever without a trace.
Hemera did not attend her funeral.
She does, however, hope that she simply went walking through the universe and came out on the other side, where her other mother will eye him cagily and her unfather and uncle goat will take her hunting.