Dad diagnosed with grade 4 lung cancer

my lovely dad has been diagnosed with lung cancer, it has spread to his shoulder and lymph nodes, the only symptom he has is he has lost his voice as the tumour has grown so it's pressing on his vocal cord! He is having treatment but I'm wondering how long he has got as I know it's terminal. Sadly my mum died of the same disease 16 years ago, I cannot believe I'm loosing my dad to this disease too. My mum had small cell lung cancer much more aggressive but dad has non small cell cancer. Does this mean he will live longer. I just want to know really