3 month baby chest and nose congestion.

Hi doctors From past 7 days my baby who is 3.5 month old having cold and cough. I went to hospital they gave ziffy dry syrup and sinarist drop. But no effect seen and medicine completed. Now his nose and chest are congested. In night after sleeping and in morning after waking up he starts coughing a lot with ghrrr grr. sound in noise throat and chest . Rest day no vibration no cough only after sleeping and after waking up.  And from past 3 days his eyes are also watery mucus sticks eyes. To open eyes need warm water unstick . At present We use sinarist oral drops two times and nasoclear saline drops 4-5 times a day but not able to remove congestion completely and remove coughing. Baby is feeding well and no fever in last 7 days. Now pls suggest what minimum medicine to use. And is nubelisation required . Or anti allergy medicine I should use or stop sinarist. I have told all things. His weight is 5.6 kg now double of birth.