Please see below. Cold and cough meds are proven not to help and can cause severe side effects. Use saline nose drops and suction the mucus from the nose as often as needed. Also, elevate the head of the crib.If your doctor ok's it, use a humidifier in the room during sleep. If these actions don't help enough, your child needs to see the doctor.
Humidify. Keep respirator tract moist by using saline nose drops, steam, fluids, maintaining room temperature between 70-72, if any wood stove, that can cause dryness and soot can irritate the respiratory tract. Otc medications are not safe to use. Get md to r/o underlying medical conditions like reactive airways.