Gu Chaoyan was marrying Zhou Huaijin, and the engagement had been established, but the Queen was Zhou Huaijin's mother, so if the Queen could get favored by the King, Zhou Huaijin would have a better future.
Even if the Queen was seriously sick, when the King decided to take care of her personally, the Queen should cherish the chance, because that was something no woman would dream about. So she did not have to drive the King away from the Queen's room.
Also… Interests came first before everything else.
The Queen was already in terrible health, so she should cherish the remaining time to get as much from the King as possible, but they did not. They did not do anything about that at all.
And they did not even mention the matter of the heir that was once mentioned by the King. Neither the Queen, Zhou Huaijin or Gu Chaoyan had mentioned the issue or given the King any pressure so that he would handle the issue.