He cares for other Coppelion members too. He might have feelings for Ibara Naruse.
Being fellow 3rd year high school students, she and Haruto seem to be close friends and Ibara actually has feelings for Haruto but it is unknown yet if it is reciprocated.They met back then when they were five years old. Their deep caring was shown in many instances. Like when Ibara was in trouble, Haruto quickly comes to her aid and at one time, he even applied mouth-to-mouth resuscitation to save her (the scene was actually caught close-up).
A proof for Ibara's feelings that she has yet to recognize was when Haruto said he examined Ibara from head to toe making Ibara wonder and blush. In the manga while looking at the stars, Ibara asked what the objective of the clean-up crew was, Haruto wanted to play with Ibara, so Ibara chased him for a while to get the bomb and leak the objective of the clean-up crew. After Haruto's return, (he died but revived back which surprised Ibara greatly, she even fainted) Ibara would keep a distance between them and would even blush if he's too 'near' like when he brought his face too close to hers made her blush greatly. Haruto on the other hand has no idea what she's feeling even asked her if she has fever.When kanon asked if ibara is important to him even though she's working with the humans ,he said his DNA just wont listen to reason.
They are close to each other. Ibara and Haruto met each other when they were five years old, but Ibara doesn't remember clearly because back then she always stared off into a distance or often zoned out.