What is the ruling on the money a person received after recovering from an illness for which he was receiving a monthly allowance from the state, and which continued to be disbursed to him without a request to update his medical report?

As long as the aid is disbursed based on a report confirming the presence of an illness, then if the person recovers, it is not permissible for him to take it; due to the Almighty's saying: "O you who have believed, fulfill [all] contracts," and the Prophet's (peace be upon him) saying: "Muslims are bound by their conditions." If he takes what he has no right to, he must return it to the granting authority. If that is not possible, he should spend it on charitable causes.