Bruno didn't exactly hate his brothers. Or at least those who he was still not necessarily on good terms with. Ludwig and Kurt had redeemed themselves in his eyes. Not that the man really took their childhood bullying to heart, as children often lacked the manners, discipline, and overall intelligence to behave themselves accordingly.
It was only natural that their own sense of inferiority would compel them to lash out against him. Such was the nature of the inferior, or such was Bruno's perspective throughout his life. But those two men had fought and bled alongside Bruno in the trenches of the Russian Civil War, an experience that had caused them to grow by more than a decade in a single year.
Any past grievances Bruno may have held against them were buried with the Red Army, and because of this, he was quite friendly with these two brothers. As for Christoph and Franz, they were old enough to have very little contact with Bruno as a child.
