dumbass bully's mom wants an apology. The only apology she should get is as follows, "I am sorry you didn't teach your little ratfuck not to abuse other people. Barring that I am sorry you didn't teach him to at least wonder if the person he chooses to pick on can pummel him into oblivion."
Also, the rat didn't receive a broken leg, the site I saw this on had that incorrect. I now return you to your previous moral dilemma.
For me it starts and ends with a little douchebag biting off more than he can chew. He chose to step up and abuse another human being. It just so happens that other human was bigger, stronger, and tired of being fucked with. Happy ending in my opinion.