Close the hole up

I asked my FIL to consider closing up the hole between his room and the guest room. I want to get someone to close it up so that they wont be able to turn the exhaust fan on. It was a stupid idea ion their part to have one there in the first place. They think they are doing the person sleeping in the next room a favor by sharing their air-cond with them, lolol. All secondhand smoke, nothing else. Smelly like hell. But i think it's time i let Gordon sleep there at night. Big boy jor. but that room needs at least a month to disinfect and rid it of all the smell and dunno what else....