If the reality is as you mentioned, you should advise her and explain to her
the rights of the husband on his wife and the rights of the children on their mother and you should do this in a kind and gentle way. Tell her that leaving her husband's house without his permission is not permissible. Instruct her to fulfill her due rights towards you with peace and love, and fulfill her rights. (Part No. 19; Page No. 226) Ask her parents and Mahrams (unmarriageable relatives) to help you. If she responds positively, it will be fine - praise be to Allah; otherwise, abandon her in bed. If this proves useless, beat her lightly in a disciplinary manner; not in revenge. If she becomes obedient, treat her kindly and keep good company with her. If she persists and reconciliation proves impossible, you should either be patient or divorce her. Allah (Exalted be He) says:
Men are the protectors and maintainers of women, because Allâh has made one of them to excel the other, and because they spend (to support them) from their means. Therefore the righteous women are devoutly obedient (to Allâh and to their husbands), and guard in the husband’s absence what Allâh orders them to guard (e.g. their chastity, their husband’s property). As to those women on whose part you see ill-conduct, admonish them (first), (next), refuse to share their beds, (and last) beat them (lightly, if it is useful); but if they return to obedience, seek not against them means (of annoyance). Surely, Allâh is Ever Most High, Most Great.
If you fear a breach between them twain (the man and his wife), appoint (two) arbitrators, one from his family and the other from her’s; if they both wish for peace, Allâh will cause their reconciliation. Indeed Allâh is Ever All-Knower, Well-Acquainted with all things.
If the cure that people have suggested to you is Ruqyah (reciting Qur'an and saying supplications over the sick seeking healing), because they think that she is affected by an evil eye, there will be no blame on you. Ruqyah should involve recitation of Ayahs (Qur'anic verses), Du`a' (supplications), or similar sayings that do not comprise Shirk (associating others with Allah in His Divinity or worship). If she suffers (Part No. 19; Page No. 227) a mental illness that affects her psychology, take her to a psychiatrist; perhaps Allah (Exalted be He) will cure her. However, if the cure involves magic spells, it will be impermissible and you will commit a great sin if you do it. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.