He''s doing it all for Minnie; everyone knows how much he hates Jaejoong. He's only accepting the relationship because it makes Minnie happy, and saving him is the only reason he's lowering himself to work with the man who ruined him in the military. he'll never forgive Jaejoong completely, but he can tolerate him for his brother. If it is along those lines, then it's as if he has some sort of brother complex, but he controls his impulses well.