<human>: Could you distill the essence of the text into 1-3 sentences?

About twenty years ago my father worked for a place installing and fixing air conditioners. Him and an associate went to a building far out in the woods to work on the AC unit.  The building was a church I believe, not somebodies house or anything. 

When they got there and started to get out of the truck, a guy in all camouflage comes stalking out of the woods with a bow drawn on them. He started demanding what they were doing there only to realize he was friends with my fathers co-worker so  he lowered his weapon. Apparently the guy looked pretty scary and unstable, he wasn't hunting in the woods or anything. 

It turns out that about 15 years later my father realized he was actually friends with this guy, and neither of them had realized it until he was telling the story about it. Some back story : The guy is HIGHLY unstable and has half a dozen mental disorders like bipolar and schizophrenia, but my father had no way of knowing that when the incident happened beyond the crazy look on the guys face. 

When my father was telling me about this, my first thought was that the second the guy lowered his bow, I would have drew a concealed carry pistol on him and told him to step away from the bow, and probably would have shot him if he didn't or if he started acting aggressive. There's no way I would have trusted having someone that dangerous armed behind my back, I would definitely feel like my life was in danger. 

Another part my father didn't know at that time : The guy was on drugs and was out there defending his pot patch
<bot>: Would drawing a pistol on the guy or even killing him as a last resort still be self defense if he had just lowered his weapon but still seemed like an unstable threat?