The thing that will save the dad is this too place inside his own house (on his property). He was just defending his family from an attacker which of whom was caught in the act. This will go down as a justifiable homicide like that Oklahoma lady who shot the dude while she was on the phone with 911 as that guy just stepped in the door. He didn't even lay a hand on the woman.
On that note: this man is awesome and SHOULD get a medal for "Badass Dad of the Year"