So the suggestion that the son was abused, in your opinion, changes his actions just how?  He 'intentionally', with forethought, stood hiding with a loaded weapon and when opportunity arose, fired intentionally.  Three men struggling, seven shots rapidly fired, and only two men hit and murdered.  Certainly not an easy task for someone who is overcome with emotion and mentally unstable because shot placement like that requires clarity of thought.

If nothing else, any paternal abuse should have inclined him to shoot all three and then his 'abuse' problems would be over.  Unless you are suggesting a "stockholm syndrome" possibility.  Then there is the attention to other details like drawing and staging the troopers guns and removing the pot, which of course has nothing to do with the story because it's use is strictly benign.

Yes you are correct, some of us will disagree with your opinion that he should have been treated differently but I doubt that will make any difference to the Dead!