This has to be one of the hardest chapters I've read in this series, I've never seen grief portrayed so realistically. Shino is finally ready to talk about her feelings she's been suppressing, but I don't think Nozomi is ready. She and Nozomi have been pretending everything was normal, and their lives have been unchanged, but now the negative effects are beginning to show.
Shino needs someone to talk to who can help her process her fear of moving on and her pain of losing her last family member. And unfortunately, Nozomi is unconsciously using Shino to help her ignore her own pain of losing the person she loved. This is exactly what Nozomi's friend warned her about. She's relying on her little sister to make her feel better, rather than being a responsible caretaker and hearing Shino out.
I don't think Nozomi's a bad person at all, but she needs to take a step back and realize what her legal ward's emotional needs are.