Thanks for posting your query.
Presence of fever
along with cough
suggests acute viral upper respiratory tract
As she is giving feed to new born, she has to take safe medicines.
There is high chances of secondary bacterial infection along with infection to new born.
You should consult with internal medicine specialist and should talk proper treatment.
She should take complete antibiotic course along with decongestant and cough suppressants.
Dr. Mayank Bhargava