Horst never really paid attention to the way Johannes acted towards him.
Johannes was always in Horst's shadow and Horst, amazing older brother that he was, liked it that way. He did care for Johannes (although he was more likely to dunk Johannes in the toilet bowl than he was to give him a big, manly, brother hug).
In any case, Johannes went searching for his own thing to do, often spending ages out on the nearby mountains playing with bones. With careful attention, Horst kept an eye out when Johannes started bringing bones home. The kid was off, Horst decided, when Johannes began to make windchimes out of the bones. Windchimes! Horst shuddered each time he heard them. They clacked together in a ghastly manner and were quite effective Horst repellent.
Perhaps it was what Johannes had wanted all along.