The King did remember that he had passed such an order, but he had been so distracted by what happened to Li Village that he forgot about his order to bring the Elder Prince back home.
He wanted to bring the Elder Prince back because he was not happy with the Crown Prince.
Yet now the Crown Prince had almost lost his life working for him at Li Village, he almost felt that he should not be so cruel to him. The Crown Prince had always been his favourite son yet he was too arrogant these days, so he needed to suppress him. However, right now the Crown Prince was keeping a low-profile and had been living at his own mansion.
He wasn't unhappy about his current behavior.
That was why he forgot about the Elder Prince and did not even think about how to arrange the Elder Prince's future.
He could not grant him the title of a lord, because the Crown Prince was going to be very unhappy about the Elder Prince's new title.