product with the best performance/price This does not directly answer your question and it may not be an option, but if you can run an ethernet cable directly

product with the best performance/price This does not directly answer your question and it may not be an option, but if you can run an ethernet cable directly from your router to your brother then he could plug in directly or use a really cheap wifi at his end if he is not more than 100 meters away. A drill and caulking agent can get through the wall if it's not a rental or sneakily out a window/under doors/through vents if it isn't obvious to neighbors or landlords and not a tripping hazard.