Thank you everyone My parents did end up taking him - only $65 rather than the $400 my dad anticipated spending. The vet said that these things are hard to heal, and that if it's not better in a few weeks, he might have to amputate part of his tail. But he wrapped up the tail, gave him a bottle of antibiotics and sent him on his way. Glad to know that it's not serious from a professional's point of view. Thanks again for the well wishes everyone