It seems to cure almost everything.
Yes, if some "method" claims to cure everything then it usually means it's bollocks... I googled this method in both Polish and English and I've found nothing in any serious media.
Here are some opinions:
forum.gazeta.pl/forum/w,22,15803056,15803056,Dr_Zenni_metoda_leczenia_tarczycy_skuteczna_.html#A
A family friend in the U.K. has the same illness and although she can certainly afford any fancy private treatment going, she still as far as I know has the illness.
Because there's no cure for Hashimoto disease. If you develop hypothyroidism due to "Hashi" (and I did) you have to take the artificial thyroid hormone for the rest of your life and that's it. You also suplement certain stuff like selenium, vitamin B12, witamin D3, omega−3 fatty acids and avoid certain stuff, like iodine, for example.