I've been dealing with asthma in my 7yo son for over 5 years now.

We have done MANY things that have not worked for us. Herbals, glyconutritionals, acupuncture, homeopathic remedies, etc. etc. The one thing that I do know for certain is that asthma is an individual situation. Meaning that what causes asthma in 1 person probably won't be the reason another person has asthma. Our most promising action so far has been an MD in St. Louis, Mo. who practices non-medically. His main form of "diagnosing" what your root problem is is called Acupuncture Meridian Assessment. The link to the article that talks about it is
http://www.preventionandhealing.com/pah-articles.htm In our son's case he had RSV at 10 months, then developed asthma over the next 2 years. I believe some of the antibiotics caused Leaky Gut, and Dr. Yu treated him for 2 parasites. We're now working on repairing the damage that the parasite did. It's a looooooong process

but it took him about 4 years to get to this place and it may take that long for him to heal.
I agree with HB about the milk thing!! Unfortunately that is not our son's problem since he has been allergic to dairy since birth. He has
absolutely no dairy what so ever. But it is a big problem with many!
Mishy - treating your aunt for Candida and Leaky Gut is an excellent place to start. If she moved to a different part of the country - like to a new state - the pollens could be different and making her react. As far has herbal remedies can can help: First of all if an asthma attack has already started a rescue inhaler is the only answer

Remember, you can DIE from an asthma attack because of the drop in blood oxygen level ( I've had my son pass out on me before

) Some herbal to try Lobelia, Nettle, EyeBright . . . but if she has pollen allergies, she may be allergic to some herbals as well, so be careful. If you have The ABC Herbal book they give some recommendations in there.
I think asthma is one of the most frustrating conditions

because the root cause is different for everyone. I hope this helps some, and that she finds relief.