I hear your frustration but this neighbour has three weeks left in your building and there is nothing that can be done that will happen with regard to the smoking in that time – and by that I mean NCAT orders and fines.
Nobody is going to come round and tell them to stop smoking. However, if they threaten or abuse you personally, then you can get the police involved.
What you need to focus on is the NEXT tenant. Send the rental agent a letter telling them that, because of the design of the building, it may be inappropriate for them to house a heavy smoker there and they should consider that when advertising the unit for rent in the future.
They may choose to ignore that but if they place another smoker in the unit, they have to accept some liability if there’s a problem. One of the issues with smokers who cause a nuisance is that rental agents don’t tell them that there has been problemin the past. A good verbal nudge in the ribs could remedy that in your case.