He was the Emperor's brother, so he could go back whenever he wanted.
However, considering that he was in the military camp and had already been conferred the title of Prince, he still acted like he did in the past.
Therefore, even if he went back, he would have to pick a time to go back.
For example, when he was free in the military camp, he could have the freedom to leave whenever he wanted. Even so, he still chose to follow the procedure of things.
Originally, he had planned to go back personally for Xue Yan's 21st birthday. However, a batch of new recruits had just been assigned to the flag barracks. They needed to train new recruits and were worried that no one would be able to train them well. He did not go back and only sent someone to send his regards back to Xue Yan.
