Are there instructions about how to work through ICU with aging parents?

Cora, what a difficult time! You might seek guidance from the social worker or perhaps someone in Pastoral Care. I've seen a situation discussed with family in such gentle terms that the family (harried of course) didn't get it! Be prepared to ask the tough questions (and to get the tough answers!) What is the diagnosis? The Prognosis? Is there a course of treatment that would improve the situation? Can Mom come back from the illness? Two weeks in ICU is a LONG time especially for a senior! Muscles atrophy and the organs don't work exactly right. Be armed with questions for the doctors. As to your exact question, I don't know of any book on the subject but you might find something with a search online.

I think that sort of handbook might come in handy for all sorts of specialties, Cora.

I'm so sorry you and your family are going through this experience. One reason, no idea if it applies in your family's situation, that ICU staff find it difficult to be candid is that, not knowing you or your loved ones well as people, they have no idea how much you want to know, or how plainly you would like it expressed. One person's plain speaking could be another person's needless cruelty. I'm sure you understand.

What to ask depends, too, on what you want to know. All I can suggest is that if it were my loved one, I would ask

what is the situation
what is being done about it
what is the realistic prognosis
what would it be wise to prepare ourselves for.

However. If you are being asked to consent to procedures or treatments, it's a somewhat different set of questions. Perhaps the only universal one might be: what are we hoping to achieve through this?

Are you or is anyone wondering if it might be humane and advisable to transfer your mother from ICU to palliative care? If you're not happy with the measures being taken - for example, if they're intrusive and distressing for your mother with little prospect of success - then a further useful question is "what happens if we don't do this?"

Will you have an opportunity to discuss your mother's care plan with the caseworker yourself? Are you your mother's health care proxy, or is someone else?

Cora I am so sorry you are in this situation with your mother. Unfortunately Drs are notorious for not admitting the seriousness of a patient's condition. Many feel that they have failed when they loose a patient. Of course if the Dr is silent the nurses really can't overstep the mark and talk candidly with you.
Can you tell us a bit more about how Mom ended up in ICU? How old is she? What is her general health like and does she have any life threatening diseases such as heart or lung problems?
Two weeks is a long time to be kept in ICU but not unheard of if she needs that level of critical care.
What does the family want for Mom? I know no one wants to loose a loved one but if the quality of her life is compromised then the fact has to be faced that she can not recover and should get comfort care which usually means Hospice, which can be at home or in a facility.
There are many experienced and knowledgeable people on this forum who will be glad to advise you as problems arise.
Do you know what your mother's final wishes are? This will help you decide what to do.
It would be a good idea for two family members to corner Mom's primary Dr in the hospital and ask him a list of questions. And I do mean corner him, some where where he can't just back away and run. Prepare your list and have the questions written down and don't let him go till you have answers. You don't need to make any fast decisions, so take the time to discuss with other family members what you want for your Mom then get back to the Dr with your answers.
There is no easy way round this but once you have the facts you may still worry, of course you will, but it will stops the "ifs and buts"
Think of taking your car to the garage knowing your car should get new tires and the mechanic says "well they are rather old but we do expect them to wear out soon" Wouldn't you rather he said "You only have "X" millimeters of tread left they should be changed today" Now you know it would be dangerous to continue to drive the car like that and you have a fact you can check - "X" millimeters. Does that make sense?

Can Mom recover from this?
What will her life be like if we pull out all the stops and save her?
Can she go back to living alone?
Will she need 24 hour care?
Will she regain consciousness, be able to speak, eat, walk, go to the bathroom?
Is she in pain?
How will the pain be controlled?
What happens if she becomes anxious and agitated.
Can she come back to the hospital if we can't manage her at home.
Can she have all the equipment she needs here at home? i.e. oxygen, hospital bed etc.
What about a nursing home?
If there is a question of surgery how would her life be changed and how long is recovery expected to take?
I am sure you will be able to think of other questions to ask but as it is Saturday you will probably have to wait till Monday for your discussion with the Dr.
In the meantime be with her and comfort her but don't overtire her.
Whatever happens two weeks in ICU is going to take weeks to months to recover from.

In addition to all the great answers, I've often found it helpful to ask a doctor, "what would you do if this was YOUR mom?"

People caring for your mom, probably feel the diagnosis for her to survive is not that good, unfortunately.