I don't know what your laws are, but looking at it from a "what's right" viewpoint as opposed to "what's legal", overall your kin is still right and the running man is still wrong. The cats had no right to be in your yard. Dogs chased them back, in the process, having no right to be in his yard. That said, they posed no threat to human life and the implication is they posed no threat to the cats thus, there was no need to kill them. There was no need to brandish a pistol threatening your stepfather either. Your stepfather bears maybe 10% of the blame and that's being very generous to the neighbor.
