@Stan loona yeah ig author did forget him or I have a theory that remember when chiwoo was inside like a fake dream where everything was fine and all so m thinking if its the same with hwan now ? Maybe this all is just the same fake dream but who knows and like others r saying maybe jin is the sibling? But I really wanted to see jin and chiwoo together 
𝓒𝓱𝓸𝓴𝓮 𝓶𝓮 𝓵𝓲𝓴𝓮 𝓾 𝓱𝓪𝓽𝓮 𝓶𝓮 - [𝒻𝒾𝒸𝓉𝒾𝑜𝓃𝒶𝓁 𝓂𝑒𝓃𝓈]