His theory isn't [i]all[/i] about the Dark Arts, though. I mean, that's the point, isn't it? That there are no "Dark Arts", just magic. You say he's quite friendly, so apart from keeping his indiscretions secret, what problem would he have with casually discussing the [i]results[/i] of his research with someone who was genuinely interested?

It's fine, if you'd prefer having no prior interaction, but I think there's some real potential here.