What Will Happen in the End Stages of Lung Cancer?

My dad is 53, and he has only told me he has Cancer.

It is in his lungs, and he has told me that it has spread all through his body. He wants no treatment.
He gets too emotional to talk about it and I can’t get exact answers from him.

He has become depressed and has started to abuse alcohol a lot. These actions along with mixing his Oxycontin Morphine makes him someone I no longer recognize during parts of the day.

I can’t tell if it has moved to his brain, or if it is he drug/drinking combo.
He is in a lot of pain, and sleeps alot. He calls me in the middle of the night,and asks me if it is day or night. He is confused sometimes, but other times is normal. He lives alone, and I am an hour away.
I am in my 20’s and the only one who knows.
I do not know what do to.

What should I be prepared for in the emd stages? How can I tell if it is near, and when I should be with him all the time (he is proud and stubborn).

I will appreciate any answers. I am in Canada, and treatments are not an option to him.

Thank you,
bb.