What "burden"? If someone is on my land who I don't want there, I ask them to leave. If they don't, depending on the circumstances, I eject them or have a court eject them.- I have a hard time that just because he Lied about the property line and left the burden on the current owner to move the line ?
- Where does it become the Sellers burden to prove he did not sell the barn or land ?
If you have to sue to eject them at some point you put down the sale documents and deed to prove you have the right to keep the other person off the land. Then, they have to show they have a right to be there. The difficult part for them is that the only proof you are saying is that the other person "thought" the line was different. I don't know how he gets that evidence in because of the parol evidence rule because what he "thought" was different was precisely described in a writing intended to be the complete sale agreement that alters that agreement. He will probably be able to introduce the fact you let him stay there for years as evidence of both of your intents in regards to the land.
What other things can he argue about intent that was not prior to or during closing and differs from the written documents? The more things he can add here, the more likely he can find success. For me, it would take a lot of evidence of a different intent to overcome clearly written documents.