Is it permissible for a married woman who is suffering from her husband’s mistreatment to waive her deferred dower and ransom herself with money to be rid of him, and is it permissible for her to marry someone who took pity on her thereafter, based on verse 229 of Surat Al-Baqarah?

What your friend did by helping the woman destroy her marital home is forbidden, for the Prophet, peace and blessings be upon him, said: "He is not of us who incites a woman against her husband." And this communication between them is not permissible by Islamic law even if she were not married, so how can it be permissible when she is a wife? This is a clear transgression against the sanctity of the husband and a violation of what Allah has commanded to be preserved. We advise your friend and the woman to repent to Allah Almighty immediately, and he should not interfere in the woman's marital problems. If the woman wishes to separate from her husband, she may seek khula' from him in return for financial compensation, as stated in the verse from Surat Al-Baqarah: "But if you fear that they will not uphold the limits of Allah, then there is no blame upon them for what she gives in return for her freedom."