Decisions to use lethal need to pass non-emotional scrutiny in court but are often made with much more emotion than logic. Reality deems that if you "fear for your life" than you are in a highly charged emotional state.
The dog is totally untrained as a guard dog but is empathic to a degree. He recognizes the wife's moods and when she unhappy with someone he might throw out a growl (although oddly he never growls otherwise). I can count on one hand the number of times he was uncontrollable by her, even briefly. However there is no way for her to physically control the dog if he is not in the mood to be physically controlled. I am a fairly large guy myself and it is a challenge for me to physically control him, although I can.
He always responds when anyone approaches the house when she is home, even me. However, he has never had to confront anyone intent on doing physical harm either so we are not 100% sure how he would react in any case.
My insurance company does not seem to care if I have a dog.
Proxima est Mors, Malum Nullum adhibit Misericordiam