Not really AIBU more a What would you do?
I have a friend, hadn't seen each other for 3 years (I've been living in a different part of the country) but we'd kept in touch by phone. I've known her over 30 years.
During the 3 years that I haven't seen her I have given up smoking.
This friend struggles massively with her mental health, always has. She doesn't work and rarely leaves the house. I go and spend the day with her once a week. She won't come to me and declines any invitation to go out anywhere on our day together. This is down to mental health and I don't mind.
Apart from her mum who she sees twice a year at most I am her only company.
The issue is her smoking, like I said I have stopped smoking but even when I did it was never more than 5 a day. She gets through 20 a day. In a tiny flat, she does open the windows but every week I come home coughing/with a tight chest.
She won't go in her garden because it's shared with a neighbour and he complained about it.
I know I need to say something but she can be very defensive and I don't want to make her feel like she needs to pick between her friends and cigarettes.