What would I tell a preschooler? Hoo, boy. I have no idea. I'm terrible at guessing or even intuiting where a child is along the developmental schedule when I interact with them. Three years old... can you talk? Ok, can you read? What about an eight year old, are they still pathologically selfish? Oh, that's only boys? Et cetera.
I would probably say that the love stays with those who are survived by the dead. It accretes and ossifies... ok, those words are probably above a preschooler. I'd say something like Love is indivisible. Do they know fractions?
Good on preschool teachers.