Wow! What a story. There is beauty though in the fact it chose you for awhile to be its guardian of sorts for a brief time.
I once had a cat in Cambodia come into my room and give birth to kittens. I only provided water and a place to stay, but never fed it any of our undesirable vegan food. Even without being fed she stuck around for a few weeks until she carried her kittens off to a new destination one by one.
It was an awesome experience, certainly not a "pet" type relationship.