Did Shiro like Shigure or was it more of a big brother little brother kind of relationship?

More like big brother

I feel like Sora did like Shigure, like a kid crushing on an adult, but Shigure looked at Sora like a little brother. I don't think Shigure would have made any advances until Sora was at least an adult.

Shigure wasn't Haru's lover??

He is u: Shigure doesn't think of Sora/Shiro in a romantic way. He's a minor lol. Don't know what anon's talking about. There was a scene in this manga where Shigure was talking to Haru about how Shiro reminded him of himself.