"No," he says before he can check himself. "The Dark Lord would never believe Rodolphus had turned traitor. He's too willing to do whatever the Dark Lord commands to become a turncoat."

That and he remembers overhearing his brother swear that not even Rodolphus' death would keep him from serving Voldemort. From helping Voldemort achieve his goals.

"But keeping him from returning. We can do that. Keep him from leaving the bar. But how does one stop a man from leaving freely? Assuming he isn't Bound that is."