I think feeling bad isn't the right word for how I feel for the brother. I think he had enough time to think about why his actions were wrong. The universe made him understand, and then our mc finally reincarnated at a time when he had actively come to the conclusion that he was absolutely in the wrong back then, making sure history wouldn't repeat itself. It makes one sad cause now they would have a chance to be what they should have been in that first life, just brothers. But it is absolutely understandable why mc is not willing to accept him as a brother, especially considering he has only lived 2 lives in one of which he died cause of him. ( he doesn't owe him forgiveness for those kinds of actions)