My mum has stopped washing, cleaning her home and there is feces on the bathroom floor. She sits in her pyjamas most days. She refuses help. What should I do?

Can you call local social services for the aging? They might be able to do something.

I might consult with an attorney to see what evidence you would need to get guardianship of her. It may be too soon, but, I'd find out, so you know what to look for. If she's still competent, I'm not sure what you could do. Based on your observations, I'd be concerned for her health though. Dealing with alcoholics who do not want help can be very frustrating. I've had friends in that situation. IT was heartbreaking. I think some of them tried to file commitment for evaluation. The attorney should know about that too. It's not easy though.

Well there is alcohol induced dementia.
Does your mom live with you or you with her?
Your house your rules. But if mom is self sufficient and humming along it's hard to see how you can force a change.
Are you enabling? Buying the alcohol?