Haruyuki saving Taku, aka Cyan Pile despite the guy kicking a lot of dogs. Because not only were they friends, they still are. And then he says how they both have to man up and tell Chiyuri everything.
The end of episode 24, with Kuroyukihime and Fuuko reuniting.
Episode 24, when Haru gets his wings back
Haruyuki's duel with Kuroyukihime in Volume 5, in which he helps get her fighting spirit back and forces her to fight seriously. For all his issues, Haruyuki can return the favor and provide support to Kuroyukihime.
In Volume 5, when Fuuko comes over and playfully teases Kuroyukihime about her closeness with Haru, Haru notices that while they have a fair ways to go before they reconnect, they were very close friends.
The part in Volume 5 in which Haruyuki comes to think of Nega Nebulus as like a family and resolves to protect them.
At the end of Volume 5, after Sky Raker informs Fuuko that she got her legs back, the two simply hug, with nothing more needing to be said, before thanking Haruyuki for his help.
While the circumstances behind Kuroyukihime qualifying for Brain Burst- her being given a Neurolinker so her father could communicate with her despite having cancer- are quite unfortunate, it goes to show that she has significantly more loving and caring parents than most of the rest of the cast.
In Volume 9, Kuroyukihime admonishes Haru for even considering flying off to the edge of the Unlimited Neural Field and leaving everyone else behind, saying that his friends wouldn't give up on him after everything he did for them. Not only does this show the kind of group that Nega Nebulus is, but it also shows that while Haru may be the sort to distance himself from others when he's troubled, there's little he won't do for his friends.
In Volume 12, Haruyuki, after hearing Kuroyukihime's darkest secret- that she was kicked out of her family after attacking her sister, thereby losing her family as well as her legion- tells her that he believes that they can rebuild Nega Nebulus, bring back the Elements, recruit new Burst Linkers, and eventually take down White Cosmos, with him at her side every step of the way. She then thanks him and says that she's grateful that she chose him.