Im glad your father was ok!
My daughter was attacked 2 years ago, the day after Christmas and that ended with 200 stitches in her face. It was a mut that weighed maybe 34 lbs. belonging to an aquaintance.
When we walk our own dogs, we carry and once I had to pull my gun on a Pitbull that was running loose. It charged us but stopped 4 feet short, I drew my gun and we walked backwards across the street and then vigilantly continued our walk. I own big dogs (shorthair pointer and irish setter) and would never allow them to roam free. When someone comes over, I even lock them up to avoid any possible problems.