Dean is such a giant piece of worthless shit, I just can't with him. I know he's just dug himself a deeper and deeper hole as he's gone along that he no longer has any idea of what's right or wrong, but I hate him. The way he looks at and treats Murphy like she's the one who killed his best friend disgusts me. I need him to get his comeuppance by the end of this season. But on the other hand, I'm sure it's fun for Rich Sommer to play this kind of role since I don't think he usually does.
While I will never stop believing that using a guide dog training facility is a good conduit for money laundering and drug trafficking, I think the writers have done a good job connecting a lot of little things together to keep tension across episodes and throw constant twists at the characters. I was waiting for at least one of the characters to try to run away since some people would entertain that as their only way out. I do hope Jess comes back, though. I expect her to pop back up (of her own volition??) when Murphy and Felix need her most.
I agree that Dean's going to have a hard time using Murphy's drug cane against her. It must have her prints and DNA all over it, but it has Chloe's, too, and Dean can't prove Murphy was in possession. And even if he could, he wants to keep Chloe out of it. She will find out at least partial truths about him, though, eventually. Maybe not that he killed a young boy, but at least some of his other crimes.
I'm hoping that Dean, unable to submit the cane as evidence, gets tempted to sell the drugs himself after he, for instance, gets one last call from Chloe's school saying she cannot come back until he pays off her tuition balance, so he unloads the drugs in desperation to make a good faith payment. (Murphy didn't buy "that much," but maybe Dean is running on fumes when it comes to bills.) But somehow it all bites him in the ass and it turns his mission to bust Nia, Murphy, and associates on its head. Gene will spearhead that discovery. In some way or another, Dean's being behind on the tuition is going to be the catalyst for something in the last few episodes.
I can't say I was surprised when Darnell admitted his real relationship with Nia, but since I honestly can't tell how old either of them are supposed to be, I also wouldn't be surprised if that's not actually the truth. Sam is already suspicious as to why Nia let Darnell off so easily, so I think she's going to poke at that as Nia feels more pressured to pretend it's arms' length handling. As the conflict grows, we'll find out it's the classic situation of Nia not being his sister, but his mother. Her mother and his grandmother died young. Nia pretended to be his sister raising him. She just can't turn on Darnell, no matter what, and that leads to some real internal fireworks within her gang as the season ends.