You HAVE to give Sachiko credit for being so involved in Hikaru's life and embracing him for who he is, especially considering her denial of his disability at the beginning.
Oki-kun telling Masato about the kids bullying him, and Masato taking off from work to stay and help despite getting in trouble for it.
In volume 4 (American version), one of the teachers discovers the abuse that one of her colleagues has put the children through and is appalled. But instead of standing by helplessly and allowing it to happen more, she calls CPS and gets them arrested, feeling guilty for not noticing this before. It takes MASSIVE balls to do this in real life, especially in regards to threats of being called a snitch.
Kanon standing up to the bullies at school when they make fun of Hikaru to her face, even though she got in trouble.
When Masato's mother, concerned about what affects Hikaru's autism will have on Kanon when she gets older, suggests she raises Kanon and sends her to another school, Masato awesomely calls her out on it and tells her to stay out of their personal business.