I've had what I think is some healing going on in my thyroid. It was a small pain on the right side, probably a nodule, and instead of backing off the Iodine I make sure to take the amount I like and even paint some on that part of my thyroid so it can get absorbed there.
I would say for your cousin to not be fearful but to continue self educating all she can about health, alternative health practices, and the use of her Lugol'sIodine so she can be confident in her use of it for her health's sake.