Been clear from the start that Dowun doesn't want any dramatic characters weighing down Lyon's regime: whether it be her own relatives (Jayang) or his own (father and brother), not to mention that nuisance bodyguard.
He'll probably need to get rid of his own father, at this rate. Their agendas are diverging.
Dowun seems likely to be distracted by his suppressed attraction to Lyon, which can only end badly for her and everyone else.
If he's off his game, she's open to attack from all corners.