It is a strange and dysfunctional family dynamic that doesn’t follow any sort of logic other than some kind of mental illness (not an excuse for her behavior, but it goes beyond rational thinking) that Casey seems to be jealous of Cindy and has a hatred towards her, but yet would still seek some sort of relationship with her. Cindy also seems mentally disturbed to lie for her daughter and throughout this case she was living in denial that her own daughter could kill her granddaughter, when all evidence was clearly pointing this out to her.
Calley was the cannon fodder both Casey and Cindy used against each other in order for each to have the one uppin’s when it mattered. Cindy wouldn’t push Casey for fear of the threat Casey held over her that if she did she’d remove Calley from their lifes.
What changed that equation was when Cindy used the car theft and money theft over Casey’s head to get her to tell where Casey was....(two calls to the police station to come and get Casey and press charges)...thus Casey then informed the family she’d been missing for a month. Cindy’s gut instinct knew well Casey had the key to where Calley was...and that no good was involved in that.
So now that she’s missing...that hold was broken then and there...Cindy’s third call that her granddaughter was missing then took place. Cindy’s tone evidences her fear and the truth about the car smell was evidencing Cindy knew then and there something treadful had occured. Reality check!
Those three calls, all on the same day were quite revealing of how the family dynamics worked.
As for jealousy, actually Casey was jealous of her own daughter and the attention the family members gave Calley which Casey felt should be hers. Keep in mind Casey has the maturity of a teenager....