My mam may have gbs. info needed.

Hello everyone,
I found this site a few weeks ago when trying to find a cause of my mams sudden inability to walk. As she became vague,disorientated and confused at the same time they thought her small cell lung cancer had spread to her brain. She was admitted to hospital and ct scan of the brain was clear and an mri of the spine was clear. She came home from hospital as the doctor said she was medically fit. Although the nurses wanted to keep her in for more tests she was not listening saying the doctor said I’m fit. I mentioned GBS to the nurse who said a lumbar puncture would be the next step,but mam wanted to come home. That was 2ish weeks ago. Since then she has become so much weaker and now finds it to hard/tiring to lift her arms. yesterday we were going to pay private to see a nurologist but when the district nurse called at 11 in the morning her blood pressure and oxygen levels were so low she had to be admitted straight away (the 999 ambulance finally turned up at quarter to four in the afternoon) Today the doctor said it may be GBS she will have a lumber puncture tomorow afternoon as they have to wait for platlets ( i think) from a different hospital. So with a bit of luck we may have a diagnosis and treatment can be offered.
I am also concerned about her confusion she has no short term memory and answers inconsistanly to questions. she’s 77 and was ‘fit and healthy’ upto sunday 30th of july then all of a sudden her feet swelled up and she ‘forgot’ how to walk. She is very unaware of her state of health. Has anyone else suffered dementia type symptoms along with their GBS?
Jo