What is the ruling regarding a brother's continued stay in an area where open widespread immorality and debauchery are prevalent, despite the availability of cleaner nearby places, and his argument that his work is in this area and there is nothing that prohibits his stay there?

It is prescribed for someone in a country where sins are prevalent to leave it for another place. This is more salvific for them and further removes them from condoning sin. Jurists have differed on the ruling regarding this, whether it is obligatory or recommended. This is supported by the story of the man who killed ninety-nine souls, where the scholar commanded him to leave his land because it was a land of evil. This is because a land where sins are prevalent may embolden its inhabitants to commit them or remove from their hearts the disapproval of such sins. Therefore, your brother should leave this city to safeguard his religion. As for work, it is not an excuse to stay. If he finds work elsewhere, he should do so; otherwise, he is not obliged to live in the same place. The servant's concern for their religion should supersede all other concerns.