...is the current queen barren or something...?
Or is it a possibility nobody wants to consider?
They screwed up with their son, their job to make another.
Last I checked, Sitting Monarchs were still responsible for their own failures.
They haven't stepped down or ceded their crown yet. Deal with their own mess.
Also, how did it go from "All Dukes And Siblings Involved With Coup Detat Were Summarily Executed By Own Hand"...
...to "Oh I Don't Want To Execute Our Son The Prince"?
Fine, maybe they have family attachment "different if it's me". Fine if the king/queen matured or times changed.
But going from "demonstrated in-universe willingness to kill traitors" to "traitors must live at all costs" is silly.