I am really sorry to hear that man 
But this is exactly the type of thing e-cigs can help prevent, nicotine and the other bases used in e-liquid are not cancer causing and deemed safe per FDA, the problem is they will not do a study on the prodcut as a whole and allow them to be marketed as a smoking alternative
Lung cancer and respiratory related diseases are caused by the inhalation of smoke from the cigaratte burning (along with the 1000’s of chemicals in a cigarette), this is what e-cigs are trying to prevent, a healthier way to go on about a habbit most do not want to break. I’m sure its hard for you to understand given you’re family has been greatly affected by the use of tobacco.
hell you could buy e-liquid with no nicotine in it at all and be 100% safe if you so choose to.