Okay, fed up... how do I support my mum my sisters carer?

Hi
Sorry I am not going to be interested how to help my sister for a minute, anorexic again, alcoholic, untreated schizophrenia, long term
My mum has stopped functioning
She is 5 hours drive away, helping my sister sell her place
Sick and frantic
She’s 77 has one untreated cataract

She has lived with 12 years of one sisters psychosis,5 of mine and 7 of my sister with late onset
I think I’d want to give up

How do I help my mum the carer?

What would help you the most?