Akira Sawada is Shin's older brother and was hinted to be the favored son. He was considered an excellent student and was expected to go off and study to take over their father's job someday. Until he left college and ranaway without a word, thus putting pressure on Shin to be just like him someday.
Very ltitle is known about Akira only that he was an over achiever like Shin. An excellent student and had their father's respect, so much so that often Shin evied his brother. Shin envied his brother and wanted desperately in his youth to please their father.
Before enrolling to Shirokin, Akira came to talk with his brother. He admitted he use to think Shin was useless and didn't know anything. But upon hearing that Shin was moving out to live by himself, he calls his little brother brave for standing up to their father. And that he, himself, envies Shin for his breaking away from their father.
Since his depature, Akira was never heard from again. Something Shin might resent him for, leaving without a word.