A: Dear Sam, Assuming that these are the only symptoms your grandson has, I would recommend using some sort of decongestant or antihistamine to reduce the runny nose. There are many over-the-counter types available, such as Triaminic or Dimetapp. With less congestion, he should cough less. For additional details, you can also check one of the previous questions: “PEDIATRICIAN: What medicine is safe to give a 3 year old for a cold?”.
If he has more symptoms, seems to be getting worse, has a fever, or the symptoms have lasted more than a week, then you should consult his pediatrician for more guidance. Your grandson could have either a cold or allergies. We are also in the midst of Flu season, so that may also be something to think about.
I hope this helps,