I would use Homeopathic Thuja 30c 3 pellets one time a day for 30 days and use
Dr Hardy's Onion and Honey syrup
One of the best things for colds, coughs, flu, sore throat, and nasal/sinus congestion is Onion/honey syrup (because it is made of honey do not give to children under 3 years old) to make it:
Take one cup of honey and add to it one cup of diced onion, one tablespoon of diced garlic, and one table spoon of diced horseradish .
To use: take one tablespoon and chew 30 times. Dose: one table spoon every hour or two as needed.