I think the first time Seungho met the doctor he was in love with someone.( His face looks bright, rosy cheek maybe blush) So the illness might be homosexual, that's why his father said that Jihwa also caught that illness. Remember when Seungho was told that he loved Nakyum, he looked shocked and said something about it used to happen in the past, a scene of younger him appeared. Maybe his father locked him up and did something cruel to change his sexual orientation. Poor Seungho.
I think the first time Seungho met the doctor he was in love with someone.( His face looks bright, rosy cheek maybe blush) So the illness might be homosexual, that's why his father said that Jihwa also caught that illness. Remember when Seungho was told that he loved Nakyum, he looked shocked and said something about it used to happen in the past, a scene of younger him appeared. Maybe his father locked him up and did something cruel to change his sexual orientation. Poor Seungho.