The guy is a scumbag, a murderer and deserves to rot in prison for the remainder of his days.
That said, I am having a hard time feeling sympathy for the teens, who, according to the article, were apparently on quite the robbery/home break-in spree. Getting shot dead by a home owner is the risk you take when you break into peoples’ homes.
I recall reading that they had broken into his home before and stolen guns, among other things, and that the male decedent had posted a pic of himself on a Facebook page--with the stolen guns.
This wasn't the teens' first rodeo, either.