Who attempts to mediate and end the conflict between Yunjae and Gom in the novel, Almond?

Professor Yun tries to mediate by setting up meetings between Yunjae and Gon, demanding his son apologize for his cruelty. Despite Professor Yun's efforts, Gon hates him, refusing to even call him his father. Towards the end of the novel, Professor Yun admits to Yunjae that he sometimes wishes Gon were never born.