You sound like those people who say, "He should have just shot him in the leg and wounded him like in the movies, he didn't have to shoot him in the chest and kill him."He could have easily held them at gun point.
So what if they do? Will that make you and their parents feel better? The people who broke into the guy's home were shot dead because they broke into a guy's home. Actions have consequences.I hope they put him in prison for the rest of his life at a min.
If you have the nads to break into someone's home, expect to get shot.If you have the nads to shoot a unarmed person