Introducing Side Characters

It's been four months since the last acciedent by the lake. Zava was in long comma. His best friends Anton, Ellena, Jeslyn, Nuel and Salsa were trying to find a cure or something to help him woke up again. Teacher of Herbology Class, Professor Longbottom said to Salsa, Jeslyn, and Nuel that there was a Unknown Black Flower inside the Forbidden Forest. The Unknown Black Flower said that can cure any diseases, sickness, even a curses. But no one has ever found it.

Does The Unknown Black Flower real?
Do they can cure Zava back?