I just don't think the Emperor believes that it is his place to look after members of his family like that; if they can't look after themselves in the atmosphereofthe court(or be smart enough to get someone to do it for them if they can't look after themselves), then it's their failing and not his. The strong will survive. If someone is cunning enough to assassinate an Empress and get away with it, he probably thinks them the 'winner' and that's the end of the affair. How he genuinely felt in private, we'll never know I expect. He did marry her for some reason,after all.
(no subject)