It's sad to see Hinami's state right now. The one person in the CCG she cares about won't visit her anymore and she is scheduled to be exterminated.
Omake from :re included some diary entries Hinami wrote, fearing the day she dies. The last person she wants to speak to before this happens is her onii-chan. And being alone drives her mad, she actually needs those books. And now they are no longer coming, neither the books nor Kaneki.
Edit: I'll give Kaneki the benefit of doubt right now, btw. If he plans to save Hinami, it's best to not associate with and act cold towards her to not raise suspicion, same as he did with Tsukiyama. He knows Eto's identity, yet he waited half a year to visit her? Maybe he wants her help.