Hi Mainelaine, and thanks for your post. While I am hopeful others in the community will see your post and respond by sharing their own personal experiences, I have something to add too.
We have had a number of conversations on this very topic, right here on our COPD.net community website. I thought you might gain some additional insight by reviewing that material. For your convenience, here is a link: https://copd.net/search?s=mullein%20tea.
I do hope you find the information is helpful in a practical way.
Wishing you well,
Leon (site moderator COPD.net)