Can't accept that my dad is dying

This is my first post on here and I'm not sure why I'm writing this. Maybe to get it off my chest or to see if anyone else is struggling with these feelings. 

In August this year my dad of just 60 was diagnosed with stage 4 cancer - the primary source unknown, but it had spread to his liver and lungs. We were told that without treatment, he would have a few months but with chemotherapy, hopefully a year. Unfortunately, my dad has just been told that the chemo appears to not be working, as he has a constant build up of fluid around his stomach, that needs constant draining. Because of this they are stopping his chemo and have given him a few weeks left to live. It just seems so unfair and I can't accept this awful outcome, even though I know there's nothing I can do about it. It's so hard hearing him say, he's not ready to go and he feels robbed of time. 

I have found myself contacting private healthcare to see if they can do anything but I also don't want to fill his final weeks with hospital appointments if they can't actually do anything. I feel terrible because he'd been poorly for a few months before his diagnosis and we encouraged him to see a doctor but I don't feel we pushed him enough until it was too late. 

I just can't quite grasp that in a few weeks he won't be here any more.