Although dementia is an illness not all have a need for continuing medical care, and go into a Care Home. If your mother has any other illnesses that require constant medical care she will require a Care Home with Nursing. We found that these were more expensive as they have to employ a team of qualified nurses instead of carers only.
My mother and mother in law ended up paying the same with M.I.L's Nhs funding going straight to the home on top of her payment.
If all her assets are below the threshold for Social Care and they pay she will still receive AA but it will go direct to SS and be included the amount they will pay. If there is no qualification for funding ensure that you are receiving or apply for AA at the higher rate.
My mother was assessed for a care home only by the Community Mental Health Doctor and her GP. My Mother is law decided to enter a Care Home herself which had very little support as it catered for self caring residents who could no longer manage homelife such as cooking and cleaning (this was due to severe arthritis). When her heart problems caused her to be in and out of hospital, the hospital assessed her for a place with nursing care and the Home made the claim on her behalf to the NHS.
Whilst my mother received a Care in the Home package without charge as soon as she went into the Care Home all funding stopped, and she had to fund herself.
When you decide on a place, I would recommend you ensure that you go for a dementia specialist.