The nails and hair do not grow after death, rather the skin begins to dry out and retract making it look like they do. Its an old wise tail, nothing grows after death except the bacteria eating you.
The brow is not a bone, its part of the skull, does not grow after death. Older variants of our species just had larger brows. This is where this wise tale comes from.

Yay science. Next you'll be saying that maggots spawn from meat, and turtles form from mud, and to make mice you need oily rags and rice in bowl.

Dragons do not exist, nor have they. If they had we would have evidence with in the fossil record, for they would have lived during the time of the dinosaurs. The legends regarding them from more recent times are merely stories.