1. People who intend to sue don’t threaten. A process server just shows up at your door one day and hands you the complaint. This guy probably complains to the barista about the price of a cup of coffee. You really think he’s going to write a $5,000 retainer check to an attorney to start a case?
2. Even though your neighbor isn’t likely to sue you, that doesn’t change the fact that you live next to an asshole. That’s the real problem and if this so called foundation crisis went away tomorrow, it would be replaced by another imaginary issue. This is what you should focus on - how to neutralize a nearby asshole.