Guests with pollen allergy and my newborn

SP

Looking for some help on this. My baby will be 3 weeks old when my brother is visiting us. My brother is allergic to pollen so the start of October (fall) is the time when his allergies are in full force (runny nose and headache). Does it pose any threat to my baby? Should I be concerned and ask him to reschedule his trip or allergic reactions don't pass on the runny nose?