He just 'hm'ed at the mention of Castiel - he was well aware that the relationship between Raphael and Castiel was far from friendly, and their family had enough disputes going on without him managing to get their enmity reignited too.

"Not intentionally. But you can't make an omelette without breaking a few continents, right? And that's if Michael had won, if he'd been-- well, if he'd lost..."

'If Michael had been killed' was still not a prospect he was willing to confront that directly. It was only because he knew that neither Michael nor Lucifer was dead that he was comfortable discussing the possibility.