Amina - just a quick initial reply to start with. From what I understand, and others here may know more, and organisations like Carers UK and Age UK will certainly know, I believe as the law stands if there is no one 'at home' to look after a person who needs care, then the state HAS to step in. It becomes a question of safeguarding.
So, if you weren't there for any reason, the state HAS to take over. They may do so by bringing in carers from outside, or they may simply move your mother into a care home.
That said, there is the issue of consent. If your mother had dementia I think (??) the state could simply remove her into a care home ,as she would lack the mental capacity to make decisions. But this won't apply in your mother's case from what you say.
However, if she refuses care, then I truly don't know if the state can look after her without her consent, whether in her own home, or by taking her into care. This is worth checking.
However, EVEN IF she is entitled to refuse any care from the state, this does NOT mean that YOU have to provide it. You are fully entitled to refuse to have anything to do with her. All that is keeping you looking after you is 'love and guilt'.
If you are 31 and have cared for her for 11 years I think you must have been barely 20 when you started caring for her. That's 10 years too many!
My own feeling is that you should move out. What the practicalities of doing so are is difficult - it comes down to money in the end. Where could you go, what could you rent, etc etc. Who owns the house/flat you live in? Your mum, someone else, a landlord? (By the way, if she is renting, and she is the tenant, be aware that as and when she dies you and your brother can be evicted and made homeless!) (that applies to private and council tenancies)
I think, from you have said, that your mother is profoundly wrong - and profoundly selfish. You may love her, but it is not reciprocated, is it? However cruel it may sound, your mother does NOT care about YOU. She could have made your life easier by accepting assessments and outside care, but no, she refuses, and lets you do all the work. That is not being a good and loving mother - it's selfish and inexcusable. You are wasting your kindness, sacrificing your life, for someone who exploits you as NO mother should.
It's absurd she turns down outside carers! Why? There is NO justification for it, other than her own selfishness. I'm sorry that sounds harsh and cruel, but what else can there be to justify her misusing you so shamefully, taking advantge of your love, and your helplessness and your sacrifice? Using up your life and precious youth when she could have made things easier for you by accepting outside help.
Yes, maybe she has depression too, but that is still no excuse.
Amina, you say you are Black British, and the rest of your family is either absent or a waste of space when it comes to what you are shouldering. I was wondering therefore, whether there is any kind of Church organisation nearby that you could turn to for some kind of counselling and emotional support? One of the best aspects of immigrant communities, even second and third generations onwards, is that they have, perforce, to develop their own community support structures, and church (or temple/mosque etc) is definitely one such source of community support. It doesn't matter whether you are religious or not, a local Church should still have 'some' degree of support for you.
Whatever your situation, would it be sensible for you now to at least work out how you might move out, and become independent of your mother and brother? Is it feasible at all financially?
I do honestly think the time has come to put yourself first. Otherwise you are simply waiting for your mother to die (or you........
If you moved out, then that might actually force your mother to accept outside help (whether by her own free will or imposed on her by the state). it could be, you know, that if you moved out temporarily, until outside help was established (or she'd been taken into a care home!), then you might be able to move back in KEEPING the outside carers (that would be a condition of you moving back in).
IF your mother accepted outside help, it might just be sufficient for you to find the situation bearable - right now it is not bearable at all.
Wishing all the best that is possible -