This guy seems to be operating with the mental aptitude of Homer Simpson. The fact that he thinks that what he did was okay is just sign of how many stupid people there are in the world.
This not SYG, this is not SD, this is just someone mad at his neighbor with a chip on his shoulder. If he doesn't get a needle I will be shocked.
1- Already covered.
2- Mostly covered. Sure you might have a reason to tackle someone with a gun but not in this case. Seeing how he was not behaving entirely rational it is of no surprise he choose a stupid move.
Get along well with your neighbors if at all possible. Go out of the way to do so. That way they will be less likely to come to your house in the middle of the night with a gun looking to kill you.
Proxima est Mors, Malum Nullum adhibit Misericordiam