are you kidding me?
the ability to have a higher form of consciousness and awareness of mortality does not make a human being more "valuable" than any other animal. i would as soon burn a man to death than burn a fly to death. of course, there's the issue of intention...i don't intend to kill millions of skin cells by scratching an itch.
right, with that out of the way, let me tell you why "failed revenge" movies fail.
if i were ave, why would i even go to the boy's father? my wife is dead, all i have left is the dog, who just got his head blown off. what to do? contact a reporter to publicize the incident so millions of uninterested viewers can change the channel? contact the police who, unsurprisingly, do nothing because the legal system is a bureaucratic mess?
nope, all you have to do is get a scoped rifle, aim it at the murderer's house and wait for him to come out the door. simple.