What is the ruling on money taken by a person from his working brother who left work while his salary continued?

Your brother is not permitted to use any salary deposited into his account until he informs his employer. If they grant it to him, it is a gift. Otherwise, he is obligated to return it because it was deposited by mistake and he is not entitled to it. You are also not permitted to benefit from it if your brother gives it to you; rather, you must inform his employer, because "one who takes from the aggressor is like him." So, if he knows that they have transgressed the right of another, it is not permissible for him to buy it, sell it, eat it, wear it, accept it as a gift, or take it as repayment for a debt. And whoever does so is like a usurper.