Stage 4 lung cancer

Hi,

I'm new to this page.

My Dad has been recently diagnosed with secondary cancer - now its lung cancer stage 4. I'm really struggling emotionally. The impact on the diagnosis has effected me greatly. He is nearly 78. He has to have PET scan soon and has seen his consultant. My dad is a very private person and keeps his feeling in and doesn't express how he is really feeling. 

My mum said she is keeping every day as normal as possible for my Dad. I find it difficult to express to my mum how I'm feeling. My gp has suggested  for me to attend counselling. 

Any advise would be really appreciated