My grandpa was smoker from age 14 till he died from emphysema at 70. His 2 kids who smoked to 40 lived to 90. Is stopping that helpful?

Yes... Smoking can result in emphysema, chronic bronchitis, lung cancer and other cancers as well like bladder cancer and esophageal cancer. We often speak of relatives who live long lives despite having smoked but these cases are rare! (so we talk about them!) it is much more common for smokers to develop at least one of these life-threatening problems. This is why it is imperative to quit smoking!
Yes. Quitting smoking at any age is associated with improved survival compared to continued smoking because it reduces the risk of cardiac and pulmonary diseases, as well as cancers.
Yes. While not everyone who smokes more than 1 pack of cigarettes per day for longer than 15 years will get copd, many will. There are significant other risks associated with smoking especially cardiovascular disease and cancer. The risks of developing a smoking related illness greatly outweighs any perceived benefit.