"The fact that the word lovesick exists, that the simple absence of a person can make you feel physically ill, says a great deal about the terrible power of the human heart." - Beau Taplin
This was exactly how Yi Chen felt. To be honest he had no idea how he kept himself going all this while. He had worked himself half to death trying to distract himself. He knew why Zi Han was distancing himself from him, that was why he was working very hard and doing whatever it takes to ascend to that position.
His father wasn't necessarily the problem but the forces that weren't impressed with his association with Zi Han. After reassuring some people and stripping power from some, Yi Chen finally achieved his goal. It didn't take much to get his father to step down.