I think Diamond knows something's up with Jerard. He's moving too smooth not to see it. He's probably still trying to figure out a way to deal with it.
Diamond knows the end game (killing his brother). He doesn't want to do it but he also knows his brother is prideful and stubborn.
D wants to build up CBI enough to where losing Jennard won't mess up the biz. Jennard thinks Diamond is unaware but I guarantee D knows exactly how his brother is trying to move. Jennard's reliance on young bois is fine for low level shyt but won't work dealing with Russians, Serbs, Mexican cartels etc. J held it down when D was in prison but he can't take CBI any further.
Liliana is going to use J's attraction to her against him at some point.