Well it sounds like the kid may or not be bullied. Kids bringing weapons to school is very common and should be dealt with properly. I don't know the kid, and since this is the media we are talking about the facts will be skewed to favor them. I would suspend the kid for a few days so that he learns to not bring weapons to school again.
I can see why they blamed minecraft since you can carry a sword, axe, bow in minecraft. However they are just looking for reasons to blame video games. For the dad's case We don't know if the stuff was locked up and the kid got the key by stealing it, either way the kid took something without the fathers permission. So blaming the father is not the thing to do. Now if he left a pistol and magazine on the table where anyone could grab it then go ahead and blame the dad. However we can't really hold him accountable. If we did, then we would be holding cops accountable because their guns got taken off their belt by a badguy. However like I said, the facts are skewed and we don't know the whole situation other than what the media has told us.