Question: why does snape and lily have a doe?
Answer: Severus Snape's Patronus was also a doe, which symbolized his love for Lily. Snape uses his doe Patronus to show Dumbledore that he never fell out of love with Lily, his childhood best friend. ... Snape's doe Patronus reveals his one true motivation throughout Harry's life: to protect the child of the woman he loved.