Same here, it makes me cry on the inside or very sad. In my Equestria Chronicles spin-off Dimensional Rim my OC Arthur R Hanson has a nightmare like this and it nearly happens, but I plan to have it thwarted how I will not tell for I don't want to spoil it.
"No parent should have to bury their child". This reminds me of the scene in The Two Towers where Theoden has just buried his son, and I think it applies to this quite well. I know its Celestia in the picture but its her parents( espescialy her mother) who are greiving. And now she'l never know that she whould have ben a big sister(and now that sister will never have the bonding time sister's should have.