Regulus fought the impulse to flush at the comment about his staring, but managed to narrowly avert his gaze, looking down at where Lucius' hands were resting on top of the closed lid. There was something clearly not right here, and Regulus was struggling with the reasoning of it. If Draco was who he said he was - and Regulus realized with a small measure of panic, it was completely possible he wasn't and this was still all a trap - than Lucius, in this state, wasn't possible. Maybe he was hallucinating, dreaming of Lucius' ghost.
"Lucius," Regulus answered, his voice a bit softer than usual, the one that his mother had trained him how to use since he was old enough to speak.
He was afraid. Even as he tried to suppress the emotion within himself, it was too ingrained into his being. What his mind could not remember, his body did. There was that instinct that he was surrounded by those he could no longer trust, he had betrayed the Dark Lord, made the mental commitment to do so, and Death Eaters of higher rank than him had been punished, tortured, killed for less. Regulus wanted to retreat from Lucius' presence, which was such a strange feeling, because he could see Draco's resemblance, whom he felt so at ease with. They looked nearly identical to Regulus' eye, and evoked totally different emotions.