Joann Cunningham and Andrew Freund Sr. are both accused of killing AJ and burying him in a shallow grave near Woodstock.
The boy was found wrapped in plastic six days after he was reported missing in April, police said.
WATCH: AJ Freund's body found 6 days after he was reported missing
Prosecutors are requesting patient-doctor privilege be waived so they can access Cunningham's medical records. The motion cites her potential drug use and how that may have related to AJ's death.
In July Freund Sr. was found mentally competent by a psychological examiner and deemed mentally fit to stand trial.
Freund Sr. was charged with five counts of first-degree murder, two counts of aggravated battery, one count of aggravated domestic battery, two counts of concealment of a homicidal death, and one count of failure to report a missing or child death. Cunningham was charged with five counts of first-degree murder, four counts of aggravated battery, two counts of aggravated domestic battery, and one count of failure to report a missing or child death.
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Cunningham also gave birth to a baby girl in jail in May. The baby is being held in protective custody.
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