I smoked for 15+ years. When my son was born I stopped smoking at home and only smoked at worked, I quite permanently about 5years ago. I would say the only way to really quite is to really not want to smoke anymore. I got sick of smelling like an ashtray; not being able to breath; going out in the cold...... basically the list of reason you would not want to smoke in the first place. I used to think that I needed it to calm down, when all it ever did was raise my blood pressure and make me a slave to it.
I made a plan and stuck to it, I started to ween myself off and had a hard quite by date. Started by cutting out a 1/4 of my daily for 2 months then 1/2 so on so forth. Then using a additive free non nicotine clove cigarette was helpful in the end (like the last 4months for me), I have friends that used nicotine free/additive free vape successfully. The thing is to not let that be a crutch and start just using those instead, nicotine/additive free does not mean anything as it is still not good for your lungs.
I realized that all the excuses I made for smoking were BS and I was wasting my money and killing myself, all things I was told for years and years but was too stubborn to listen. Big picture was taking the money I was using for a few months and setting it aside and realizing how much money I was spending on literally killing myself. It has been about 2 years now since a good family friend past away from lung cancer, he smoked for 30+ years. After watching the horrible crap he had to go through with makes me hope I don't have to go through it.
Now that I am working out again and doing more physical activity again, I kick myself, as more often that not my lack of ability to bring in oxygen is what stops me from pushing harder. At least her husband has a good amount of smoke free time under him and will likely be a huge help for her quitting.