"Good Doctor" Joo Won's biological father seems to be in a terrible health condition.

September 16, the 13th episode of the KBS drama "Good Doctor" featured Park Si On (Joo Won) fainting as soon as he sees Park Choon Sung (Jung Ho Geun).

Even in the midst of the panic after Park Si On faints, Park Choon Sung yells at him saying, "Wake up right this instant!" Right then, Park Si On's biological mother, Oh Kyung Joo (Yoon Yoo Sun) shows up and says, "Stop this right now. Where do you think you are?"

Seeing his wife for the first time in a long time, Park Choon Sung says, "I knew it. I knew you two would be living happily ever after together."

The couple decides that they need to have a conversation. Oh Kyung Joon tells Park Choon Sung that she will give him all the money she has if he goes far away from Park Si On. Park Choon Sung replies "For whom would I do that for? I'm going to take some benefits from my son before I die."

Suddenly however, Park Choon Sung begins coughing violently and is unable to control his body. The hand that was covering his mouth is covered in blood.

As a result, Park Choon Sung ends up staying at Oh Kyung Joo's home. Even then, he is unable to control his anger and tells Oh Kyung Joo that he is going to kill her. Choi Wook Suk hears about the news of Park Si On's father and shows up right away. When Park Choon Sung sees him, he gets even angrier and says, "I knew you two would stick together."

Park Choon Sung begins to spit up blood again, which makes Choi Woo Suk panic after sensing something is seriously wrong.