Leonardo wasn't sure if he believed that Lucius hadn't known about him, but he guessed it didn't matter either way. It took him off guard, the comment about his mother's lips, but he ignored the way it made his skin crawl. "Thank you, sir," he said instead, because that was the proper response to a compliment from one's father. At least, he thought it was supposed to be a compliment.
His father wasn't someone who danced around the important topics it seemed. "Well...the other boys in the dorm are already talking about...the resemblance." He spoke carefully, choosing his words. "I thought that sooner or later it would get home to their parents, and what I've learned of Slytherin politics, I thought it better you be prepared." He straightened his spine, because he wanted his father to think him smart and strong, not scared and weak. "I know you have a wife and a son, and I don't want to cause problems." Best to get that out there, even if his very existence would cause a problem. He wanted his father not to view him as a threat. It would be easier to get away from his Uncle that way.