Do not presume that your mother has dementia.
By what you write, there seems to be some other underlying medical issues. Confusion and forgetting things can happen when an older person has a urinary tract infection. My mother went completely "loopy" and it turned out to be a urine infection and pneumonia.
You mother is falling over - this can be due to balance problems either from infections in the inner ears or spinal issues. Elderly people an easily get low iron levels and low Vitamin B12 levels, this can also lead to feelings of depression, change of character and forgetfulness. Low iron levels can make her feel very depressed and with her falling over, it may be that there is no enough oxygen getting to the brain.
Your mother needs an urgent appointment to be seen by her doctor.
Is there anyone else that can take your mother to see her doctor urgently, with a list of her symptoms. Perhaps you could find out if a doctor can come out to see you mother urgently.
You can purchase at a reasonable cost, urinary analysis sticks that you can check your mother's urine at home. Alternatively, if you are able, get a sterile urine specimen jar and get your mum to do a mid stream urine sample and send that to the doctors to be analysed at the laboratory.
Your mother needs medical attention URGENTLY.
Let me know how you get on.
Seventy three is not very old. There are various kinds of dementia. Somtimes the deterioration may be reversed, and other times there is inevitable decline. Square one is to get a medical proxy so you can discuss the issues with her physician. Lately, because of federal privacy regulations, physicians will not discuss these issues with even a close relative. At the time of her exam review her medications and her nutritional status. Statins have been connected with memory decline, for example. Look for a physician or a practice that specializes in geriatric care. They are more likely to be helpful. Give her lots of hugs and TLC. The falling issue concerns me. Clearly she needs a complete in-person work-up. I don't have any easy answers, but don't give up on her.