Dumbledore did hand him the “You’re wrong, think about it for 5 minutes” cue in a way that got him to do it. That kind of thing is crazy helpful.
And yet Dumbledore and everyone else he though of asking couldn’t solve it themselves for twenty years. For the last ten years, Snape would have told them if they’d even made the right suggestion.
Dumbledore did hand him the “You’re wrong, think about it for 5 minutes” cue in a way that got him to do it. That kind of thing is crazy helpful.
And yet Dumbledore and everyone else he though of asking couldn’t solve it themselves for twenty years. For the last ten years, Snape would have told them if they’d even made the right suggestion.