A:
If the situation is as you mentioned, she does not have to do anything other than
to perform Tawbah (repentance to Allah) and Istighfar (seeking forgiveness from Allah) for the curses she spoke. She must also ask for the forgiveness of her parents-in-law, if one or both of them is alive, if this is possible and there is no fear of trouble.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.