Wondering about RSV.

Domo

My son is 4 months old and he has had a croupy sounding cough for a few days. He went to my parents for the weekend, and since coming home I’ve noticed his cough sounds worse, and he is very cranky. He does have a doctors appointment on Tuesday for his needles so I’m definitely going to mention it to my doctor. I’m just wondering when RSV becomes a concern. What are the symptoms I should be watching for. TIA. 😕