Spear tactics of Xiao Ding?

Adiri asked Simon about Diarmaid Irwin, and Simon immediately perked up. Before he could speak, Adiri smiled and asked Simon: "Why is Batur doing so well?"
"Yeah." Simon nodded heavily, and then told Adiri excitedly about Diarmaid Irwin's recent performance.
As Adiri's only "biological son", how could Adiri really just send Diarmaid Irwin to the training camp and then ignore him? Not only the students in the training camp, but even the people around Hans, many of them were spies planted by...