After reading the previews of the fourth and fifth episodes, the answer is obvious. This Ba Weiguo is not the real Ba Weiguo. When Ba Weiguo walked out after the car accident, he asked someone to save him. It was the man who killed him with a shovel, and then he turned into Ba Weiguo to inherit his family's property. This was discovered by Wang Yimiao (his present wife). She is madly in love with Ba Weiguo. This man killed Ba Weiguo, so she wants to get back at this man (this is the fourth episode). So she drugged him. This medicine is for mental patients. It has serious sequelae, such as damaging people's brains and nerves, and then abusing the man after he lost his ability to take care of himself, resulting in so many ferocious wounds on his legs. So the terrible laughter Yang Liying heard came from Wang Yimiao, and the screams came from that man. Because Yang Liying's mother hated Yang Liying, Yang Liying was drugged bit by bit, because she said she wanted to torture her slowly. Wang Ma (nanny) obviously knows the truth, so she supports Wang Yimiao's revenge. Later, she was drugged, because she thought Yang Liying was innocent, so she wanted to save Yang Liying. She is unfriendly to Yang Liying because she wants to get rid of Yang Liying so that she can stay away from danger. But Wang Yimiao obviously thought that Wang Ma had betrayed her, so he immediately injected her with a lot of drugs, which made Wang Ma paralyzed. That's roughly it, so Ba Xiaohao is the son of Wang Yimiao and the fake Ba Weiguo, and Yang Liying is the daughter of the real Ba Weiguo and her mother, so they are not related by blood.

Attachment: In the fourth episode, the doctor said that Ba Weiguo was in a coma. He didn't know until he woke up. However, after Ba Xiaohao and Yang Liying turned around in the camera, he suddenly opened his eyes, and his eyes were clear, indicating that it might not be so serious. I wonder if he is really crazy. We have to wait until the end of episode five.