I agree with naomi here. The issue of benefits, whilst annoying, really is irrelevant to the issue. People not smoking in their own homes is a regular sight these days. I'm not sure why they don't just stop smoking altogether, if they find the stench so bad that they don't want it in their own homes.
Stopping smoking is made so much easier these days, unlike when I gave it up 36 years ago. You can even get anti-smoking help on prescription.
Here in Wales, smoking now accounts for only 24% of the adult population, which is much better than years ago, but we now have the hard core left. It always puzzles me somewhat that the people who can least afford to smoke are the ones most likely to do so. Education is needed. We still have some to go it would seem.
Cupotee...my sympathy to you. Not sure what advice to offer, beyond the fact that this wonderful summer, with its high temperatures won't last forever, so you will be able to close the windows soon. What a pity you have such ignorant neighbours.