There is an unusual phenomenon called ICU psychosis. When people are in the ICU, they are almost in a different world. Time means nothing, they are awakened at odd hours, their sleep is interrupted and they are often sleep deprived. They are, many times, on heavy doses of medications, there is all kinds of machinery and tubes attached to them and there are many disconcerting sounds from that machinery and from other patient's rooms.
Sometimes people are in terrible distress or even dying within earshot of the patient's room. Scary stuff.
Add that to all kinds of medical people poking and prodding and doing all kinds of tests, and the pain of the procedure itself.
One of the things I have read and actually done for my husband was to bring in familiar photos of family, friend, pets. And ask people to send cards, then you read the well wishes to your mom. Sit really close to her and read a familiar book to her, or the newspaper or just talk, gossip, whatever you have done as a normal part of her life in the recent past.
This helps the person see themselves in a more normal setting.
Also bring in a calendar. That was another hint. You can mark off on the calendar what day it is, and you can talk about the weather and what time of day it is and what is going on with your family.
With my husband, he was most concerned about the household bills and keeping the house books straight. So I brought those in and we went through them together.
If this is what it is, it will clear up when she becomes more stable and is transferred to a regular unit.
