Does God answer the prayer and oath of a person who asks that his family be lost and die, and that he die a bad death if he returns to sin?

Swearing an oath on the Qur’an not to return to a sin confirms the obligation to abandon it. If you swear by Allah and then return to the sin, an expiation for breaking an oath (kaffarat yamin) becomes obligatory upon you. Your supplication against yourself and your family upon returning to sin is forbidden by Islamic law, based on the saying of the Prophet, peace and blessings be upon him: "Do not supplicate against yourselves, and do not supplicate against your children, and do not supplicate against your servants, and do not supplicate against your wealth. Do not coincide with a moment from Allah, the Blessed and Exalted, when there is a bestowal of grace, and He answers you." Scholars have differed regarding the answering of this type of supplication. We hope that your supplication is not answered, out of Allah's mercy, and it is preferable that you supplicate to Allah to protect you from the evil of what you invoked upon yourself. For Allah does not answer people's supplications against themselves, their wealth, and their children when they are angry, out of kindness to them, just as He answers them with goodness and blessings.