Old Mu had been operating in the military for many years, cultivating a host of loyal followers as well as various other forces; naturally, the Luo Family coveted his position.
Otherwise, Luo Linhao wouldn't have ended up in Funan. But it also goes to show how venomous that group was, to be able to lay hands on a child. Old Mu labored abroad for the sake of the family, sending back so much wealth every year, yet they couldn't even accommodate his wife and children.