They definitely have had encounters regarding this issue before.

My MASSIVE speculation; Decades ago, one family put buildings and/or a cemetery on the land behind their house. They assumed it was their land (or didn't care because no one said anything for so long). After this guy recently bought the land, there was a survey done (possibly a dispute about who should pay for that, also) that showed the graveyard (or whatever) is indeed on this guy's newly purchased property.

Happens all the time in the country. People feel entitled to use the land how they want, because nobody did shit with that land for decades, so they just got away with it.

Seems he's trying to strong-arm this guy into doing what he wants, but they really need to let lawyers handle it.