So Sirius was an arse. There was nothing new there, and he doubted that any amount of talking would solve that. He also knew that no matter what he said the first reaction was the true one: you did this to my friend. Again, an arse, but nothing new. However when Remus spoke up, he stared at Sirius and he was certain that they were sharing the same confused look.
"Remus...." he started, not sure how to ask if he'd lost his mind, too. "Getting to talk? I thought that's what we just did. I told him, he listened, we didn't hex each other." He frowned. "What else are we supposed to talk about? Sirius, is there anything you want to talk about?" 'No' would be a very good answer, because Regulus couldn't imagine what else they'd have to discuss.