It's simple. He's neither. The boy is a victim, not a criminal, and certainly not a hero.
He killed somebody. That will stick with him for the rest of his life. Whether he did it intentionally or not doesn't really matter. If he did, then it is fair to say that he has deep psychological issues that might take a long time to resolve, if it is possible at all. If it wasn't intentional, then he will have to live with knowing that he killed his father for the rest of his days.
His father sounded like a despiccable person. I will not assume that he was a killer, or killer to be, or that his Nazi tendencies would have gone far enough to actually do more than protest in front of synagoges. We don't know that. We can't say 'Well, nazis used to kill people, so he would have killed somebody eventually, so he deserved to die.' It doesn't work like that. You can't judge somebody on the grounds of what might or might not happen in the future.
By hailing the boy a hero, and appreciating the fact that he killed his father, you put yourself on the same level as said father. You are no better than those Nazis that wanted every non-white person dead. There is a person, a Nazi, with extreme views that clash with everything you believe in. That person hasn't commited a crime though, he is merely voicing his opinion. It is a very unpopular, disgusting opinion, but still - he has the right to say what he thinks.
Now you don't agree with him, so you want him dead? Isn't that exactly what the angry little Austrian man with the moustache did (And yes, he was Austrian, NOT German)? Removing everybody from the face of the earth that didn't fit into his warped, sick picture of what society should be like. Do you know how many Germans died because they didn't agree with what he was doing? He didn't just kill those that weren't white, he killed everybody who didn't agree with his ideas and ideals. (Or had them killed, since I don't think he actually bothered to do it himself).
Applauding this child for killing his father is the same thing. You think somebody deserves to be killed because they don't live up to your standards. Because they don't fit into the picture of what YOU think is right or wrong. There is absolutely no difference between that way of thinking, and other extremists. Your hate is no different than theirs, it is just directed at something different.
Just to clarify, in case there is any doubt, and to avoid any misunderstandings:
I do not condone racism in any shape, form or fashion. I think Nazis are the lowest of the low, and I do believe that the world is certainly a better place without that guy spouting his hate everywhere.
That said, at the end of the day, a 10 year old boy took a human life. No matter what we thought of that life, it's tragic, and the boy will be traumatized forever, by the event, the trial, and whatever might happen afterwards. If anything, I feel deeply sorry for him.
And on a completely different note....why would a known Neo-Nazi get custody of children??? What the hell is wrong with people????