your situation is very much like my sons. Yeast big issues and GSH makes it just explode in my sons case and very well yours too. This is fact that you should not take GSH when u know you have a big yeast issues. I know what you mean about wanting to keep her on it. Take her off the oral and stay with the nebs.
Put her on high strenght garlic and grapefruit seed extract for 2 weeks, no probiotics, then stop that and go on high strenght probiotics with biffidum bacteria in it as well as acidolphillus.

I am a medical herbalist, nutritionist and this is a very good way to elimate yeast, its worked well for my son. He now has no yeast issues and can east sugar etc. As for stoppn staraches I tried this and my son lost soooooo much weight. Your call.

hope this helps
smoneill@xtra.co.nz