I have thought of this problem and offer a temporary solution. You say that the different wings are on separate power sources or w/e, i'm not an expert but you should be able to walk outside and turn the power off. This is not my solution though. Once the power is turned off, (this is for your own safety), enter his room, and find the power points. You should be able to take the cover off and see wires connected to the back of the power point. Find a small screwdriver and undo the screws which hold the wires on, this will disconnect the wire and stop the point from working. Push the wires back into the wall, place the power point back on and it will look no different. It just won't work. If my siblings were pulling this shit while i was going through uni, that's what I'd do. It will at least buy you a few days peace. Come back to me if you need an excuse if they come blaming you, i'm very tired right now.
While these are most definitely first world problems, if your brother is truly being a dickbutt of the aforementioned proportions then that's not cool. My two cents
