Inheritance semi-detached house - Will or land register decisive?

Or what do you think?

There was never talk of a bargain price, but rather an appropriate price.

Are you sure that a community of heirs is registered in the land register? Communities of heirs are not intended by the legislator to exist permanently and almost certainly do not last 30 years... Aren't the three siblings rather registered in the land register in the "normal" way after the dissolution of the community of heirs following the grandfather's death? Then the current inheritance dispute does not matter in the sense that this one son is registered in the land register independently of the grandmother's will.

If I understood you correctly, the third brother did not inherit anything from his mother (except the compulsory portion). That is exactly how you think it should be (I do too, by the way). His inheritance share came from the father. Presumably, he did not neglect him.

Then put the house up for auction and buy it. Then everything is fine. Or, probably better: talk to your brother first. Maybe he is nicer than you think.

Joint heirs' communities are not intended to last permanently by the legislator and almost certainly do not last 30 years.

leaves the siblings completely alone with the care