7 month baby is congested, but he doesn't have a cold? Why?

My son has been congested and w/ a dry cough off and on since december Dr. says it's a cold and prescribed albuterol because his breathing was heavy It's just the cold season so everyone is sickies even myself and my 5 year old have been off and on with the dry cough and my mother in law too it's stubborn and keeps coming back!! Just try and keep him away from sick ppl so he can recover fully and not catch anything else which he might since his immune system will be down. Prop him up when he sleeps to help w/ the breathing and keep using the nasal aspirator to clear up any boogers and get a humidifier. Good luck and just do what you can to make him comfortable.