I would definitely call the sheriff (or whoever) just to 'chat' not necessarily make a report letting them know that the neighbor was rather frightening, threatening though not violent etc, you are worried because he was so intimidating. Find out what they have to say, they may encourage you to make a formal report or not want to be bothered. Be totally reasonable either way MZ, I have had a nasty neighbor problem and while I didn't expect the police to take 'sides', that's not their job!!!! Because I was calm and reasonable AND polite (without being smarmy) they at least knew they could count on me to be reasonable ahead of time, because things DID escalate. Your inquiry lays a groundwork for any future problems where police or the Sheriff may be needed.
In this case, if he does start making complaining calls to various places, your getting a relationship going with whoever you can is a good thing. If he's so obnoxious, they may already be sick of his calls, complaints and obnoxiousness. They still have to take his calls seriously, or as much as they can, but if he's a real pain, they may welcome someone who can counter his bs. It isn't brown-nosing, it's being a concerned citizen!
In this case, if he does start making complaining calls to various places, your getting a relationship going with whoever you can is a good thing. If he's so obnoxious, they may already be sick of his calls, complaints and obnoxiousness. They still have to take his calls seriously, or as much as they can, but if he's a real pain, they may welcome someone who can counter his bs. It isn't brown-nosing, it's being a concerned citizen!