If he does he might as well burn the whole country whole together. The King's position is literally worthless the council is intertwined with many important figures each of them having their own armies. Also the people of the kingdom do not actually stand with their king. Even during the war there were only a few commanders that were actually on his side most of them were sent by the council to make sure he never returns . So basically he is weakening the council one by one..
Hope that helps I did leave out a few things so lmk..

Can someone whisper to me why the emperor doesnt just kill duke truyd? Like i get that he is the leader of the dragon’s heart circle or smth, but surely if its such an open secret that he is actively poisoning the king, and the emperor already has the rep of being a deranged madkiller, wouldnt it just make sense if he kill the duke for annoying him (he is a tattletale for sure dude keeps yapping) or! If he would be abdicated for murder someone high ranking, Stage an assassination or arson or accident that will off him.