It is a very strange and sad time.
I often pretended that I was the future me travelling back from a couple of years in the future. Thinking about how grateful I would be to see Mum, even though she was very ill, and to be able to do little things for her.
I took the odd photo and video on my phone under the pretext of being able to show my OH who wasn't as able to take as much time off. I am very glad I have these now, although two years later I haven't felt able to look at them.
I tried to remind myself that someone who is dying is, by definition, someone who is still alive (albeit very unwell). I tried to take it day by day and concentrate on keeping Mum comfortable and feeling supported. We had "said all there was to say" already, more or less, as she'd been sick on and off for several years.
But it was an odd sort of gift to know the score so that I could drop everything else and spend a lot of time with her. Those last couple of months were very precious and it meant a lot to just be together.
I found an uncharacteristic assertiveness when it came to fighting her corner on the ward. Something a doctor friend had said resonated with me : "children are supposed to outlive their parents", they said. Mum had looked after me when I was vulnerable and helpless, and now it was my turn and duty (and privilege in an odd way) to see her through her final illness.
OP have you got older friends who have been through the same thing - in particular, losing a parent from cancer - who you could talk to? Who would be straight with you?
I remember when my FiL died, decades ago now, we were in our early 30s, so, maybe about your age(?) and it was our first go round, as it were, and we were a bit at sea. DH had older colleagues who were very helpful when it came to untangling hospital euphemisms and deciding what to do (take time off etc).
Best wishes to your Dad and yourself and do come and ask here or on the Elderly Parents board if there's stuff that you're struggling with. I'm so sorry you're going through this but you are not alone. 