That was my reaction to it as well, but according to her a precondition of involuntary manslaughter is recklessness & she did not believe that he was acting recklessly, but rather was merely freaked out by the large number of people around as well as the tenseness of the situation.
However, carrying a weapon gives you a great deal over the people around you. I would suggest that somebody carrying a weapon should be held to a higher standard of ethical conduct, regardless of whether or not they are properly trained in the use of that weapon. If you want to carry a lethal weapon & can't be bothered to receive proper training & end up killing somebody as a result, it's on your head.
As someone who carries one frequently I wholeheartedly agree with your last paragraph, but being held to a higher standard also doesn't necessarily mean your mom got it wrong either, since she thinks he believed his life was in danger apparently.
