I just realized that the Royal family sets a precident to hire illegitimate children are treated. Instead of punishing the children, he should set an example to punish adulters and those who abandon their children.
It seems like the Duke may be on a suicidal mission to make the Emperor realize how many people he's hurt by being a shit. But that might just be wishful thinking on my part. I sure hope the twins don't forgive Riolu so easily, he did majorly betray their trust and only start helping when it was honestly a bit late.