That's a sickening story and I hate to hear about these kinds of things. I would attribute these types of incidents to our society as a whole.
I don't think it's the fault of the video games or the companies who make them but, there's a reason why there are age limits on games now.
With that said, I am a gun owning adult who loves violent video games and I wouldn't let my kid play those types of games without first getting a clear understanding of his thoughts on it.
There's no handbook to parenting but, it would seem that people in this day and age would rather let their tv's raise their kids than do it themselves.
Despite the fact that the kid is obviously a sociopath, I can understand why the father forgave him. After all, it is his baby boy. As a parent you can't help but feel like you failed him somewhere along the line to see this kind of end.