The steamy bath is a must, expecially at 3 am in the morning when breathing (living) is the hardest. Oregano pure drops on the walls of the bathtub and steam has done wonders for my kids. The Maximum Restore or for reall little one just plain Anti-Plague is the answer, it breaks up the mucus in the lungs ands you spit it out the next day or so.
Group is bad, I had it as a child and use to lay in bed wondering if I would have another breathe, many times I knew I could choose to die by just stopping the fight to breathe.
It is all about diet, I grew up on a dairy farm and it is no wonder I went to bed each night full of mucus.
Non Mucus forming foods eliminates this self made disease, we stop all food, put the kids on red raspberry tea, use anti-plague and it is over in a day or 2.
Age 11 is a little old to be having Croup, hopefully this is the last time!