Hi my name is S. and I may have a suggestion. First off most of my 3 children have had numerous lung ailments, whooping cough, bronchitis, asthma and even vial pneumonia (before 2 years old)
There is no asthma in my family but I had allergies that would come and go as I was growing up, mostly a hayfever type.
For whooping cough bundle them up and sit outside in the damp cool air. That really works like a charm, but I couldn't tell you why!
We bought a breathing enebulizer or breathing machine. You squirt solution in a little cup attached to a mask and turn on the machine. It turns the liquid almost immediately into a vapor and they inhale it for approximately 10 minutes. You can use albuterol or a saline solution. It helps clear the passage ways and you breathe easier
This is what I used when they first contracted the viral pnueomina, which can develope from a cold to pnuemonia overnight. It helped immensely and usually the children fell asleep while using it or right after because they could breathe so much easier.
Granted that was 10+ years ago but even now when the kids start to develop a cold or allergies act up, they ask for a breathing treatment. Even my husband is a believer after suffering a horrible bout and relapse of a cold/flu virus 2 years ago. He was receiving treatments in the morning and the night. It seems to speed up the recovery time.
Also what plagues your children as babies and toddlers alot of time they grow out of it when older. I don't know whether their immune systems become stronger and more tolerant, but my children's touch of asthma disappeared around 5-7 years old. They never needed an inhaler but had persistant coughs especially when laying down at night.
Their allergies only kick in when really windy or certain times of years when everything is blooming and not even with consistant symptoms. We just use over the counter Claritin on an as needed basis.
Good luck and kudos to you for the more holistic approach. Years ago I bought a book, which I have since lost. But it was a great herbal book which gave examples of plants to grow in individual planter to create teas to handle different illnesses. 1 pot was for flu another for cold, another sore throat etc. I used it for my husband and myself, but I never
really develop the planters, like I should have. I only messed with it for several months. Life just got too busy!
Hope this helps and good luck and God Bless