You have my sympathies. My mother was diagnosed with pancreatic cancer last year and went through several periods where we thought the end was just a matter of days away--she was even in hospice. But she managed to rally and is doing well right now, though she will likely die from this. Plus, the treatment (or something else) has really affected her memory, and I can't have the same deep, meaningful conversations I used to have with her. She was my go-to person for advice on big things, so I really miss that.
You've already gotten good advice, but I want to add that you need to be good to yourself, too. Sometimes being with an ill/dying parent can be so intense that you need to step away. My sisters and I were good about giving each other breaks so we could go live our normal lives for periods of time, and almost forget what was happening, because we needed that and our kids needed that.
I echo the "be present" advice, though I sometimes find that one hard. But I have to keep reminding myself not to let anticipatory grief interfere with the time we have remaining. She's still here. There is time to grieve when she is gone. That said, I've been told that it's OK to grieve the loss of some things now (for example, our deep conversations) and not to deny my feelings, and that feels right, too.
Losing a parent is a hard, hard thing. Because it is the natural order of things, and everyone goes through it, I somehow didn't think it would be so difficult, but it is. I look around me at people who have lost their parents, and I am in a little awe that they all survived-I had no idea it was this hard. And yet, they are all OK, they are all living their lives, so someday we will likely be OK too.