We have braeathing treatments with albuterol and saline for cough and honey over 1 years old We do that throughout the day. Then for bed time, we do a steam down, then suction, we put baby vapor rub on their chest, cool humidifier on their room, owlet, and breathing treatment right before bed or while they are asleep.
Steam up your bathroom and have him breathe in deep there. Put extra pillows under his head when he sleeps. Post nasal drip attributes to coughing.