After suffering from a flu for a week, my mother has dementia today?

A change in mental status should be reported to her doctor, immediately. Call right now.

Don't check, don't look it up on the internet, don't mess about - get professional medical advice from a qualified practitioner. Do it now.

Hello again. Much thanks to all of you who gave your concerns. I took my mother to the emergency ward of a hospital today. They discovered she had pneumonia in one lung and she was low in sodium and yes, dehydrated. They put her on IV fluids. There were CAT scans made on her head and xrays on her chest. Body life signs on the electronic monitor were below normal and she is very weak in movements. Her mental state is still in question. She will be alert for a few seconds and then become incoherent. Being the agent in mother's advance health directive and holding my promise to her on not letting her die in a hospital, I will be bringing her home in a couple of days. I will take care of her till her end, which seems to be near. I have been caring for her for many years, good health and bad, that it is not that difficult to do. She still calls out my name in her weakened state.  I love her very much.

What Barb said. Do it now.

Check for a uti...if she was taking antibiotics for the flu, this could have exacerbated a urinary tract infection.

Delirium and dementia are often hard to distinguish from each other, but dementia is usually gradual in onset and delirium is an "all of a sudden" thing.  Think of mom's delirium as a "symptom" and report it to the doc right away.    (((((hugs))))))).

And from the Mayo Clinic website, causes of delirium:
(as you can see, some of these need to be dealt with immediately; don't let the doctor put you off.  If you need to, call the EMTs)

Causes
Delirium occurs when the normal sending and receiving of signals in the brain become impaired. This impairment is most likely caused by a combination of factors that make the brain vulnerable and trigger a malfunction in brain activity.

Delirium may have a single cause or more than one cause, such as a medical condition and medication toxicity. Sometimes no cause can be identified. Possible causes include:

Certain medications or drug toxicity
Alcohol or drug abuse or withdrawal
A medical condition
Metabolic imbalances, such as low sodium or low calcium
Severe, chronic or terminal illness
Fever and acute infection, particularly in children
Exposure to a toxin
Malnutrition or dehydration
Sleep deprivation or severe emotional distress
Pain
Surgery or other medical procedures that include anesthesia

I had this flu a month, and are just now able to eat and there was virulent diarrhea. I’m 64 years old and are chronically ill. The end of the first week I was delirious, very delirious says my hubby. I remember being ‘unable to talk’ meaning I was out of it, and annoyed about that.

That didn’t happen again during the next three weeks. I’m trying to gain weight now. Oh and I do not have dementia.

You're bringing her home once she is stable, right?

Let them give her all the IV antibiotics and fluids that they can. It works quicker that way.

I'm sure you're a great "nurse" and we can tell that you love her very much. But let them do everything they can for her while she's there.

Bless you both.

My mother's doctor said it might be delirium from not eating much for 5 days. All she had during that period was water, juice, and a little protein drink. She could not eat solid foods. I have to take her to a specialist later. She seemed to be alert at the doctor's office and answered some of the questions without problems. Her eyesight has become very impaired that she cannot see who is in front of her at all. She did have a period of clear thinking today at home, recounting how to deal with her death. I'll report back here when things settle down a bit. This flu has been very severe on her. Possibly the meds too, we gave her what we had in the cabinet that had worked before.

I will get her to her doctor today.