The problem isn't that people do not know what to say to you when you tell them that your mother is dying it is that people want to say something wise, moving, insightful or spiritually uplifting.
Perhaps because so many of us are from small families and so few of us have experienced the practical details that attend sickness and death people have trouble understanding the deathbed realities of the grieving family.
The address book
My mother had an old well-thumbed address book. I think she bought it decades ago and over the years she had drawn lines through many of the addresses. In some cases my mother had simply lost touch with the person named but in a heart-breaking number of cases the struck-through addresses had the word "dead" written over them in red ink. But we could not simply pass on because of the red line drawn through the name. That person might still have living parents (unlikely), be survived by a spouse (somewhat less unlikely) or by children and grandchildren. We would search through the ragged address book looking for candidates.
We sat down and made a list of the people who needed to be called and shared the names out amongst us. We discussed what needed to be said and what was better left unsaid. And then we began making the phone calls.
How many times can one say 'my mother is dying?'
How many times times can one politely and patiently answer the questions?
"Are you sure?"
'Yes,' I would say, while thinking, would I call a near stranger to tell them this news were I not sure?"When did you find out?"
'Well,' I would say 'I am fuzzy about the exact day,' while thinking, please please don't be offended that my first response was not to call you.
"Is there anything I can do?"
'No,' I would say, while thinking, if I knew of anything anyone could do for my mother do you not think I would have already asked that it be done.*
You know that these people don't mean to hurt you. They may even think that they are helping you by giving you 'a chance to talk about it.' But talking about it doesn't make you less tired, less worried, less concerned about your father's health, less concerned as to whether your mother is scared or in pain.
Every second talking to someone else is a second you are not spending with your mother. And your mother has very few seconds left. You don't know when she will draw her last breath but you do not want to spend some of those last few precious moments of time telling yet another person 'my mother is dying.'
So you answer the questions with as much speed and as little emotional involvement as possible.
And then you go back to your mother's bedside. Talking didn't help. Sharing didn't help. Answering questions didn't help.
Your mother is still dying.
* There are some wonderful people do don't say vaguely "Is there anything I can do?" but instead make suggestions as to what they could do. This frees you from the fear that you have misunderstood the nature of their offer. "Would you like me to pick up your groceries?" or "Do you need to have any books returned to the library?" are much more useful offers than a vague 'anything.'