and dark vaginal discharge
could be because of infections of the lower genital tract. If she has itching and/or smell she will need to take antibiotics to control this infection.
However, with these symptoms she also needs to have a gynae check-up and a Transvaginal Ultrasound
to rule out ovarian masses. So there is nothing you can really do except wait. She may need a Hysteroscopic examination to examine the uterus
All the best....