That is absolutely not true. In fact it is intuitively ridiculous. Of all the cancers... lung cancer is pretty cheap. There is no practical treatment. Other cancers are orders of magnitude more expensive, mainly because they ~are~ treatable. Same with other sorts of organ failure. There are far more expensive ways to spend time as an older person without the relative cheap things supposedly endemic to smokers.
Lung cancer is just one of the few cancers and illnesses by smoking.
"Coronary heart disease
Atherosclerosis - fatty deposits in the arteries which can lead to strokes, peripheral vascular disease, gangrene, and aneurisms
Buerger's disease, which can lead to gangrene.
Cancers Lung
Mouth, nose and throat
Larynx
Oesophagus
Pancreas
Bladder
Stomach
Myeloid leukaemia
Kidney.
Respiratory Chronic bronchitis, emphysema and other lung diseases
Recurrent infections in the airways
Damage and loss of efficiency in the lungs.
Other disorders Peptic ulcers (ulcers in the stomach and duodenum) - increase both in incidence and the time they take to heal
Tobacco amblyopia (defective vision) and other eye diseases such as cataract
Reduced fertility. "
Anyone smoking in the presence of others is contributing the other person's discomfort and health consequences and this is true especially for children who have no say in what is forced upon them.