and the mother had a house full of guns, she (the good guy with a gun) was not able to defend herself from the bad guy with a gun.
GIANT theory fail
WTF? The kid stole her guns or he had access to them. That is not a responsible gun owner in the least. She is not the good guy here. She created a monster and it, quite literally, blew up in her face. She trained him, she kept him within arms reach of firearms and she paid the ultimate price for it.
How you can equate "good guy" to the parent that created this monster is beyond me.