An AR-15 or Mini-14 firing 223 ammo from an extended magazine would have probably saved them from those painful and extended anti-rabies treatment.
The animal attacked him and his nephew while they working on a project outdoors, in his driveway. Where they live, there is rarely any need for a firearm for self protection. Occasionally, but rarely.
I live a few miles northeast of them. I have seen at least one bobcat in Concord, MA (maybe a mile north of the Old North Bridge), which is a few miles east of me. When I take my grandson sledding in a remote area, I worry just a little bit about bobcats. More nowadays.