Is it permissible to dispose of money brought by a Muslim jinn, which he had obtained from a sorcerer who died?

A legal ruling is not based on dreams, and jinn can steal a human's money and deceive them. The closer a person is to the straight path, the further they are from the devil's authority. Satan may appear in the form of a person and claim to be a prophet or a saint, and he may bring stolen food or drink.

Regarding the money the questioner found, if its origin is unknown and its true nature is ambiguous, it should be treated as lost property whose owner is unknown. This money is not a "luqatah" (found item requiring specific announcement). If its owner is not found, it should be returned to the public treasury (Bayt al-Mal) or spent on the welfare of Muslims on behalf of the public treasury. If there is no just ruler, it should be managed by whoever is in charge. And Allah knows best.