It just dawned on me. The reason why the service items in my client's hospital bill were redacted was to protect his privacy under HIPAA (Health Insurance Portability and Accountability Act). Unless the creditor obtains the patient's consent to release his hospital bill (considered a medical record), the creditor can disclose only the minimum amount needed to collect the debt.
While my adversary takes heed of this rule, he is rendered unable to establish the reasonable value of services for which it claims that my client is liable. Since it has produced no contract and no account statements to demonstrate an agreed-upon price, it must rely on recovery based on quantum meruit(reasonable value for unjust enrichment). But how can it prove the reasonable value of the services if it can't prove the services themselves?