To stop coughing at night you should use a humidifier or vaporizer in your room at night.
The humidity added to the room can help add moisture to your lungs and help slow down or stop coughing at night.
I start coughing more in the winter months at night when the air is dry and the furnace is going and after using a humidifier in my room at night I cough less.
I also have a whole house humidifier to keep moisture in the air which helps a lot.
You can also stop coughing at night by taking some cough medicine and even NyQuil which will help stop the coughing and help you sleep.
Inclining your head and taking some honey or some warm tea with honey can also help stop a coughing at night problem.
You may also need to take decongestants and if the coughing is allergies you need to take some allergy medicine and try to find the source of the allergy and get rid of it.
Make sure to change your furnace air filters in the winter and change them in the summer as well if you have central A/C because that dust can get thrown around in your home through your furnace and A/C vents.