sounds like she has seasonal flu or viral. Continue with Paracetamol tablets for fever. She should take steam and offer her plenty of warm fluids like soup or rasam or tea and simple food like idly upma khichdi bread. Ask her to rest and gargle with salt water if she has throat irritation. She should improve with this.
Next Steps
Consult online or a physician in person if symptoms do not improve or detiorate.
Health Tips
Never take antibiotics like erythromycin without doctor consultation. With a platform like practo you can ask a doctor n number of questions and take prescription thru private chat. Then why risk self medication? For eg In your wife's age group a female could be
pregnant also.. a doctor would never prescribe erythromycin without ruling out pregnancy. So try n avoid self medication as a rule. All the best n hope she gets well soon..