Is it permissible, in Islamic law, for a man to marry a woman by an 'urfi (customary) contract, with the knowledge of her brother and the testimony of witnesses, in order not to قطع (cut off) the pension of the woman whose husband has passed away?

If the pillars and conditions for the validity of the marriage contract are met, then the marriage is valid. However, it is not permissible for the wife to continue receiving her deceased husband's pension if the granting authority stipulates, as a condition for her eligibility, that she be unmarried. This is based on the general statement of the Prophet, peace and blessings be upon him: "Muslims are bound by their conditions in what is lawful."