You can use a bulb syringe to auction mucus out of his mouth if you need to and run a hot shower and stand in the bathroom with the door closed. The steam will help. Also, you can try some Vicks rub inside of a wax warmer.

Please do not give cough medicines to an infant. They need to cough in order to clear the mucus out of their lungs. Suctioning with normal saline, especially before feeds, and as needed + keeping the temp down with Tylenol is your course of action for baby. Viruses can take 7-10 days for the body to fight off☹️

hylands cold and cough is for infants. works great! there's a daytime and nighttime option.

zarbees is good, also tiny cold syrup it's night time medicine. both should help.