Who has custody of these children and how is the grandmother involved? Did you report this behavior to CPS? As for your question, you can ask for a Lincoln Hearing and have the children speak directly with the judge with their attorney present. You can require the children to testify at a hearing. Their attorney can object, but if you insist, the judge will permit them to testify in open court, with the attorneys questioning them. What petitions are pending?
There is no legal bar to prevent a 7 year old from testifying so long as the Judge is convinced after speaking to him that he knows the difference between telling the truth and telling a lie. I find that children often make the best witnesses.
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Since you posted here, I assume this is a family court proceeding, but why is there no CPS component or criminal proceeding going on? Does the grandmother have custody or court ordered visitation? Anyway, In family court, the judge can interview the child in chambers as part of the trial together with the child's law guardian.
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