Antibiotics would do no good against a virus.
Your right the only treatment if detected early enough is In intensive care, patients are intubated and given oxygen therapy to help them through the period of severe respiratory distress.
The earlier the patient is brought in to intensive care, the better. If a patient is experiencing full distress, it is less likely the treatment will be effective.
Ribavirin causes error catastrophe during Hantaan virus replication. It's too bad they needed the autopsy to make the diagnosis.