The person I think who knows more than anyone is Cindy's therapist.
Once those records are subpoena'd, more will be revealed.
I think Cindy was getting advice from the therapist, telling her - Cindy - to take actions that she normally wouldn't have done.... i.e. make Casey responsible for stealing, lying, neglecting her child. Kick her out of the house. Press charges for stealing Cindy's parent's money. Obtain custody of Caylee.
When Cindy told KC what her plans were, KC went berserk and threatened to take Caylee and never let Cindy see her granddaughter again.
Anger--->Threats---> Verbal abuse --->Physical Altercation
Cindy may have continued to see the therapist after Caylee and Casey left. From her post at her Myspace July 3rd, Cindy was obviously very distraught. The therapist is prolly the one that first called Casey a sociopath and then Cindy repeated it to Casey's friend(s).
The therapist prolly advised Cindy to call 911 and have Casey arrested and when she did, felt so uncomfortable and guilty for doing so, as she had never made Casey be responsible for her actions in the past. (Remember what the teacher said about Cindy showing up at school, etc.)
Cindy then immediately went back to her own way of thinking and doing things, re Casey's behavior, lies, threats, etc..... without the therapist's help/advice. Thus the drastic change in her demeaner immediately after the 3rd 911 call.
Since there are confidentiality laws, the therapist can not give any info re what he/she knows about the case... unless the records are subpoened.