I spent two years living with my parents to nurse my father back to health. My sister made excuses to get out of it by saying she was ill and then her husband was ill. This was a lie. When my mother got ill after my father died we agreed to alternate days. I was ADAMANT that I would help out but would not move back full time. Seven months later, my sister faked a back injury. When that ran thin, she moved onto stomach issues and refuses to come back. How do you force someone to accept responsibility without starting a war?
Best wishes to you.
Can Mom afford a full time caregiver, live in, or assisted living at some level? Does she have a home you can sell or any assets to help pay for assisted living or whatever level of care she needs? Those are the calls and decisions you need to be making right away. If it's a care facility, line up some to visit, and make the best choice.
Since you've been left in charge, you find the best care and choice for mother. Present what you find to mother, and tell sister what your decision is. Your sister has removed herself from decision making by not being reliable despite her promise. Let mother know you can't do this any longer, so these changes have to be made so she can get the best care and be safe.
Good luck.
What has changed since your other thread in early October?
Why do you allow this to be all on you? What does your mother say? Does she recognize the unfair toll this is taking on you?
Do you have POA/HCPOA? What are her needs? What are her finances? Could living in a facility be a possibility?
I am sure the daily responsibility is draining on you. What sort of care does mom need? Is it really daily? Think about hiring a companion, on mom's dime, for the times when you cannot do this. You need a break. Perhaps mom would do well in assisted living, then you can visit when you want as a daughter, not a caregiver.
I see you asked a similar question back in October. Review the answers you got there. Responses are going to be the same here.
https://www.agingcare.com/questions/how-can-i-cope-with-two-sisters-who-are-ditching-their-responsibilities-and-have-left-me-holding-eve-452812.htm?orderby=oldest
My suggestion is to do for you and your loved one because that’s all that matters now and all that will matter later. Time and life straining, absolutely. But it will all work out as it is supposed to and this difficult time too shall pass. I promise you though that after it’s over it will be you feeling strong that you were there every step of the way. Bless you for being there for tour loved one. My thoughts are with you.
Take care of yourself.
One brother (not local thankfully) will never be welcome in my life again, but he won't likely ever visit mom again, so even-steven there! (he was the one treated like a god came to visit!)
For the other, it is like pulling teeth to get a response - actually pulling teeth is easier, quicker and less painful!!!
I had to finally realize being angry with them only impacted me, not them. So, I manage everything for mom, no longer ask or consult with them about anything. They don't ask either, so I guess we know where they stand!