Why does the woman look worded?

M: What’s wrong with you, Mary? You look worried.
W: I’m all right. It’s all because of my father.
M: Did he blame you?
W: No, not at all. He is always very kind to me. I’m worried about his health.
M: Isn’t he feeling well? In my opinion, he is strong enough for his age. So what’s wrong with him?
W: Yes. He often says he knows himself well. He’s got a bad cold, and coughed day and night. The doctor said heavy smoking had caused his illness.
M: Yes, he smokes too much. Smoking does great harm to his health. He should have realized this.
W: He should have. But he says he would rather die than give up smoking.
M: That is the problem. I suggest you have a good talk with him.