Eucalyptus is great and keep a humidifier running in his room. Cool mist NOT a vaporizer. Hot Mist (Vaporizers) grow germs. If persists I would get to the Dr. The following is the signs that he may have croup.
Croup is characterized by a loud cough that may sound like the barking of a seal and may be accompanied by fast or difficult breathing and sometimes a grunting noise or wheezing while breathing.
At first, a child may have cold symptoms like a stuffy or runny nose for a few days and may also have fever. As the upper airway (the lining of the windpipe and the voice box) becomes progressively inflamed and swollen, the child may become hoarse, with a harsh, barking cough.
If the upper airway becomes swollen to the point where it is partially blocked off, it becomes even more difficult for a child to breathe. This happens with severe croup. With severe croup, there may be a high-pitched or squeaking noise when breathing in (this is called strider). A child will tend to breathe very fast, and the stomach or the skin between the child's ribs may seem to pull in during breathing. The child may also appear pale or bluish around the mouth because he is not getting enough oxygen.
Symptoms of croup often worsen at night and when the child is upset or crying. In addition to the effects on the upper airway, the infections that cause croup can result in inflammation further down the airway, including the bronchi (breathing tubes) and the lungs.
Most, though not all, cases of viral croup are mild. Breathing in moist air seems to relieve many of the symptoms. Doctors will also sometimes treat with steroids, which helps with the airway swelling.
One way to humidify the air is with a cool-mist humidifier. Having your child breathe in the moist air through the mouth will sometimes break a croup attack. Or try running a hot shower to create a steam-filled bathroom where you can sit with your child for 10 minutes. Try cuddling and reading a bedtime story while doing this to help calm your child.
Sometimes, during cooler months, taking your child outside for a few minutes can help break the attack because the cool air can shrink the swollen tissues lining the airway. Parents can also try driving the child in the car with the windows down to bring in cool air.
If your child has croup, consider sleeping overnight in the same room to provide close observation. If you are not able to break your child's fast breathing and croupy cough, call your child's doctor or seek medical attention as soon as possible.
Medical professionals will need to evaluate your child if the croup appears serious or if there's any suspicion of airway blockage or bacterial infection. Medications such as epinephrine or corticosteroids may be given to reduce swelling in the upper airways. Oxygen may also be given, and sometimes a child with croup will remain in the hospital overnight for observation. As with most illnesses, rest and plenty of fluids are recommended.