Sadly, this is happening all too often lately and it's about time the law was changed to help innocent pets being attacked too. But after saying that, a staffie that ripped the head off a little Pomeranian in my home town is still being held by police and the owners have appeared in court and await sentencing. Maybe it depends on the severity of the attack. At the very least your friend's Dad should maybe present the owner of the vicious dog with the vet's bill, although that may be easier said than done.