How long has she been on antidepressants. Have you heard of Kelly brogan. She has a book a ,mind of your own, that states your friend should have blood work to see if there is a nutritional or hormonal issue. Then a diet with no sugar, gluten or diary. Exercise 20 mins daily. She may be on the wrong med for depression. Sounds like it’s making her orthostatic hypotension which means her blood pressure drops when she stands up. Side effect of meds.