Viral Fever, Cough, Yellow Green Sputum. On Rotocaps, Januvia Medication. History Of Asthma, Diabetes. Treatment?

My mother was under treatment for asthma and diabetics from 17th April. She took rotocaps for asthma and januvia 50 mg (daily one) for diabetics. She became alright in 2 weeks. sugar level became normal and asthma was under control. On 4th may she got viral fever and cough . We met a doctor and he gave few medicines. (asthalin Expectorant, Dolo 650, Combitide 250, zostum O and montek LC. But cough increased and the sputum became yellow and sometimes greenish. I took her to hospital again (another doctor) , he gave another medicines. she has taken the medicines 2 times now. but even now the cough has not yet reduced. She is not to lie down. she hasnt slept from last 5 days. her body, throat and head is paining because of the cough. A lot of sputum is coming. Please tell me why her cough is not coming down, why she is not responding. please help