I’m sorry for your losses; but it’s an extremely difficult addiction to quit.
Besides stress, it also helps people to center their minds and think. Many years ago I had a doctor in DC whose patients included lots of high-profile journalists. He said that those had a VERY hard time quitting, because smoking helped them to write.
You are fortunate never to have started.
I thank my lucky stars that I never did smoke, especially having grown up in a family with five members who did. And back then, our mother smoked through every one of her pregnancies. I was the baby. I hated the smell of cigarettes, and the ashtrays were the worst. What a disgusting sight. In grammar school, when I sang with the choir, I could always tell my mother was in attendance because of her cough. She used to send me to the store to get her a pack of Camel's. She'd give me enough to pay 25 cents for the cigarettes, and whatever was left, I got penny candy with.
I realize that even though I never smoked, it doesn't mean I won't get cancer at some point. My health problems have been mostly abdominal. I had four separate surgeries that began in 2010, and ended in 2015. No one else in my family ever had any of that.