I do think the law may be different in each state. Here, CPS will get involved with a parent if a child has a mental illness and is not getting the child treatment. The juvenile court here also has a program for kids in trouble with drugs or other things-the family is assessed by the courts social workers and a decision is made from there, whether to involve CPS or DMH. A parent here will not be charged with neglect unless they know their child is using and does not get them help, or of course if the parent is doing drugs with their kids or supplying the drugs. Which happens more than you want to know.
As far as the 'no contact order'-if there is indeed one in place-
Would that be a decision that a judge would make? Or can CPS make that call?
And what to they mean by "joint investigation"? Is there another legal matter going on, or are they talking about Isabel's case?