Shiro may have spent a long time away from his sister but he knew when she was upset. He could tell she was angry at him. He didn't blame her really. While he had been described as a bit of a loose cannon, Shiro could never get angry at her. He'd get angry at himself first before he'd get angry at her. As she asked him why he hadn't seen her, he turned his back against her. He didn't want her to see the fact that he had tears in his eyes. He resumed to take a long drag out of his cigarette as he pondered a response. He couldn't lose his composure, not around her.
Finally, he mumbled out, still talking in his native language, "What did you want me to do, Leyu? I couldn't go home! You know how uncle is not that understanding..." He didn't want to continue. He had killed two people that night. Yes, it was in self-defense but he was also anti-mutant up to that point. He was certain he scared away the girl he loved too. "Besides, I'd rather you believe I was dead then live with the shame of who your big brother was." He didn't answer her question entirely. It still gave no reasoning on why he hadn't seen her when he was reunited with his father.
He decided to turn questions back at her, "Why are you here?" He hoped she wasn't a mutant too. It would no doubt throw her into this huge mess. "I doubt it is to ask me those questions."