@hawkeye10,
Once more I am sorry for your mother death however a shotgun blast that destroy a large part of a person lungs or anything else that cause harm to the lungs could had resulted in such a death such as viruses , germs, chemicals and on and on to anything that cause great harm to the lungs.
It have
zero and I mean
zero to do with lung cancer and no doctor would list the cause of death as lung cancer.
Now would you like to talk about lung cancer and it proven link to smoking or not?