My Dad died in '99 with lung cancer, and my Mother died in '07 from emphysema. After Dads death I took care of Mom daily, because she was attached to an oxygen bottle 24-7-365 for 6 straight years. Mom weighed 78 lbs at her death.
She could not drive, or walk more than across the room on her own. I did all this while working 12 hr rotating shifts and raising 3 kids of my own.
I breathed in HEAVY 2nd hand smoke the first 18 years of my life. As a child, riding in a car with 2 chain smokers was unbearable.
I HATE smoking, and yes, if anyone has a right to, I do.
Congrats on improving yourself. Never go back.