Osamu rolled his eyes, staring at his brother -- though he didn't really seem all that annoyed. Just amused. "Y'know, I didn't expect ya to fall in love with a guy, 'Tsumu," he commented. Watching Atsumu fall in love made Osamu happy, even if he didn't act like it. He cared too much about his brother's feelings to be upset. It was something to think about, considering they fought so often. But Osamu knew his brother was being vulnerable right now, and he wanted to support him.