Dad just diagnosed with small cell lung cancer stage 4

Hi,
I'm a little, well a lot sad today, my Dad has been diagnosed with stage four small cell lung cancer. He has no symptoms and went into hospital for something else. Unfortunately, I know a lot about the disease as a dear friend's sister has it and I've read a lot about it. I'm scared. My Dad knows nothing about how potentially serious it can be and he thinks he'll beat this with chemo. We're going to discuss his treatment on Friday and I don't know how he'll cope with the devastation if they tell him it's terminal (and my poor Mammy). Any advice on how I can help him through this? I'm being really positive when I'm around them but I'm petrified. Is there any hope for this type of cancer? I'm sick of the doctors already asking me if I'm medical when I ask them questions, they also said chemo is their only option, why can't they do radiation or immunotherapy? Any advice as well on what's ahead would be appreciated and how I can balance spending time with my own family (in Dublin), my family at home (Kerry) and work (Dublin). Obviously I want to spend as much time as I possibly can with my Dad and family. I have two young children as well who seemingly have been acting up since I've been home. I miss them terribly (and I have only been in Kerry six days).
Any help would be so appreciated.