I think the terminology in regards to defending yourself or family is "reasonable force" so given the circumstance, restraint may be an option or anything else up to lethal force, again circumstance dependent and determined in a court of law. I know the primary question here concerns firearms but in reality there are many things that can kill or injure. In my experience a drug or alcohol affected individual with or without weapons is often more of a risk to me than one who has safely stored firearms and is expecting a visit from a health care provider or similar.
