If she is your friend then you should not be passing judgementvon her habit no matter how bad.
I will go
half-way on that side of the debate. You should
not judge. That is not a free pass for doing nothing.
But let's suppose the problem here was that she owned a Humvee with a souped up engine, wide tires, a tungsten brush bar and a locker tranny--oh, and she drinks tequila, lots of tequila.
When would you intervene? Before or after she ran down a baby carriage?
But this is smoking. One in three die directly from use.
My doc told me that even with the aerobics I do (one hour StairMaster per day, two hours as a younger man) it took me
ten full years to return my lungs, health and life expectancy to the numbers of a healthy man who had never smoked.
Imagine this. A dozen years from now you go to visit your friend in the hospital. Body weight, perhaps ninety pounds. They've replaced all treatments with a morphine drip. Darth Vader has a better singing voice.
Do you want to think, "Gee, I probably should have said something..."