How does God answer a mother's prayer against her daughter for illness and death, even though the daughter has repented of her abusive and insulting responses to her mother and no longer wrongs her?

It is not permissible for a mother to supplicate against her child, as it is forbidden by Islamic law. This is based on what was narrated in Sahih Muslim from Jabir (may Allah be pleased with him) that the Prophet (peace be upon him) said: "Do not supplicate against yourselves, nor supplicate against your children, nor supplicate against your wealth, lest you coincide with an hour in which Allah is asked for a grant and He grants it to you." Some scholars hold the view that the supplication of parents against their children may be answered if it is due to disobedience. However, a mother's mistreatment and supplication against her child do not permit the child to insult or revile her, for the mother's right is great and is not forfeited by her wrongdoing.

The tribulations that befall a child are not necessarily a response to the mother's supplication. Tribulations may have other causes, and they may be a sign of Allah's love, as stated in the noble Hadith: "The greatest reward comes with the greatest trial. When Allah loves a people, He tests them. Whoever is pleased, for him is pleasure, and whoever is displeased, for him is displeasure." Therefore, one should be patient and have a good opinion of Allah, frequently supplicate for well-being, and strive to be dutiful to the mother.