What should I do about my brother who sells obscene magazines and newspapers, given that I don't speak French and my documents are not in order?

Your brother must stop selling magazines that contain indecent pictures and limit himself to selling newspapers that are free of them, while repenting and resolving not to return to such an act. You must enjoin him to do good and forbid him from evil. It is permissible to abandon him if that proves beneficial. As for you, we advise you to leave this country, as it is not permissible to travel to non-Muslim countries except out of necessity or need.