Bless her I know that feeling all to well. Hashimoto is a inflammation problem she will also most probably have low stomach acid causing burping and mistaking it for indigestion and so will gps, try some digestive enzymes before meals. She may also be deficient in vits and minerals. Tests for vit D, B12 folate her iron may be low too so full iron panel including TIBC % saturation, ferrtin, She should also think about avoiding gluten dairy and soya oh and the hardest I’ve found is sugar. These are all triggers! Selenium is a great antibody reducer for Hashi try to get this tested b4 supplementing with 200mg a day.
Have you heard of ‘stop the thyroid madness’ its a group on Facebook and there is a book available to buy on amazon also Isabella Wentz follow her group. Her books are Hashimoto’s Root cause, hashimoto’s protocol they all have lots of info.
As for how long it will take depends on how far your daughter will go to advocate her own health. Going gluten free helps with brain fog.
My life stopped abruptly for 2 years believing gps and endos new best, they didn’t in my case. oh don’t let them put your daughter on anti depressants ! Good luck I hope your daughter figures the quickest way back to functioning with all this reading. NDT IS A GAME CHANGER X