Is the work of a brother who is employed by a company that finances projects and individuals with fixed-interest loans, and who gathers clients and receives a commission and a fixed salary, permissible or impermissible?

Interest on loans is usurious and unanimously forbidden. This is supported by the statements of Ibn al-Mundhir, Ibn Hazm, Ibn Abd al-Barr, Ibn Qudamah, Ibn Taymiyyah, al-Ayni, and al-Shawkani. Accordingly, a job that deals with usurious interest is forbidden and must be abandoned, especially since permissible alternatives exist.