Your daughter probably feels terribly sad and misses her pets; maybe she hasn’t expressed these feelings to you enough yet. Her insistence that the dog will never die is likely her way of saying that she couldn’t stand to lose the dog too. Empathize with her sadness and worries. Let her know it’s normal to be sad after losing a pet and that it’s OK to express her sadness in words, or by crying. At her age, she’s unlikely to understand that all living things eventually die and that death is forever, so instead of emphasizing these concepts, tell her you understand why she wants to think the dog will never die. This way you aren’t agreeing, but you’re offering understanding about her wishes and helping her differentiate between fantasy and reality.