Terrible news Rogerthecat. My heart goes out to you and your family. My step Dad died of Lung cancer in 2000 when I was 14. It was heart breaking. He smoked from a young age but also had a very poor diet (fatty foods etc) but looked healthy till he started.
From 14 years old till 25 I was massively against smoking and turned down all offers of cigs from mates etc. I did drink however quite a lot. Then from 25 to now I stopped drinking and started smoking. Can't even explain why I did. I will hopefully stop before my 30th birthday in two years. I have hypertension so I'm more at risk of strokes which took all my grandparents from me.