In my experience it is much easier to get Carer Allowance than it is to get either Disability Allowance (which is for people under state retirement age) or Attendance Allowance (which is for people over state retirement age).
I managed to get Attendance Allowance for my Dad, by filling in the forms myself, but I would most strongly advise that anyone thinking of applying to get professional help with filling in the forms. Citizens Advice, Age Concern, etc, can help you with this.
They will not only know the sort of things that the person who assesses the form will be looking for, they will know exactly what to write, and they will also most likely think of many things you have come to take for granted and would not write down yourself. The forms are now less "guided" in that instead of asking many questions, you are just asked to describe problems at length in your own words.
Carer Allowance, on the other hand, is just a matter of filling in a form that is mainly tick boxes, and getting the person you care for sign to declare you spend at least 35 hours a week caring for them (with the usual provisions for people unable to sign). There is no person making an assessment of needs, etc - you either qualify or you don't. The person you care for must be getting DA at the middle or higher rate, or AA of either rate. You can also work and earn a certain amount and still get CA.
The decision process for DA and AA can be quite long - up to 10 weeks - but that for CA is much faster.
If your income is low, and you have only small savings, then you might also qualify for Income Support, on top of CA.
Importantly, if you get CA, then you will also get National Insurance credits, which will boost your elligibility for State Pension.
There are also other benefits you might be able to get, such as Council Tax Benefit.
There are many rules, of course; if you have not applied for any benefits, then you should be contacting your Social Services office or Citizens Advice ASAP.
Remember - these benefits are a right.
Finances are usually mentioned at some point during a patients followup assessments - in fact, the visiting occupational therapist started to talk about Attendance Allowance and what did the carer do for money and got flummoxed when I told her I;d sorted that all by myself, including filling in the forms!