It depends on what the latest wt rag has said about it or the milieu of the current cong.
I know this because over the years I have asked my jw that very question, would he, if needed protect me & our kids? if that was the only option? Sometimes the answer was, "well I would have to think about it" ( never mind that if someone is in the act of strangling/raping your wife or children there is not a whole lot of time to mull it over) other times it was, "yes, you are allowed to protect your family even if it involves deadly force". So there you have it, depends on what the wt has to say about at the moment. That was my experience anyway.