What should a questioner do regarding his mother who does not pray, nor fast, nor pay zakat, nor adhere to the legitimate hijab, and is he obligated to pay her large usurious debts if she dies, knowing that she does not intend to pay and prefers spending on travel?

One must thank Allah for the blessing of guidance and strive to invite the mother to the best way, with encouragement and deterrence, and seek out someone who can influence her. The questioner is not obligated to pay off her mother's debts, neither during her life nor after her death, unless she leaves behind wealth, from which the debt should be paid. The heirs are not demanded to pay the debt because it is on the mother, not on them. If she dies as a Muslim, it is recommended to pay off her debt as an act of piety towards her. People must be warned against giving the mother money.