Purchase of land with an old barn that is also used by the neighbor

why don't you get an expert? I am a layperson, but why should the neighbor pay or do anything at all if YOU want to tear down?

because part of the barn is on our property and the other part on his. the barn that he built in 1945 with the previous owner of our land.

therefore our question is, do we have to ensure that his part of the barn remains intact. theoretically, we are also not responsible for the fact that he built the barn together with the previous owners back then.

because part of the barn is on our property and the other part is on his. the barn that he built in 1945 together with the previous owner of our property.

therefore our question is, do we have to ensure that his part of the barn remains standing? theoretically, we are not responsible for the fact that he built the barn together with the previous owners back then.

expert no idea. it's actually building law. maybe ask a lawyer?

He has half a barn that he uses and wants to keep. It is located on his property. How do you get the idea to just tear it down?
If you want to tear down your part, you have to make sure that his part stays standing.
According to the sketch, you’re lucky it’s so small. Leave it standing, use it as a garden shed or something similar.