Dealing with a sibling who is the full time caregiver.

I will try and make this within the space limitations. Sister lived with mother all of her life. They had a good set up for many years. Mother paid for a place to live, groceries, utilities, etc. Sister provided transportation and some of the general household expenses. No doubt that mother had more than she would have had if sister had not been there. Sister raised her two children in this household.
Through the years the other children couldn't "go to grandmother's house" because it was also sister's house and she had her children there so it made it difficult for the rest of us.
Father was alcoholic and abused all children both physically, emotionally and sexually. Finally when me and sister were grown we had him thrown out and they got a divorce.
All went fairly well until about 10-15 years ago when mother reached her 80's and wasn't able to help out very much. Sister really began to complain. They rented the same house for over 50 years and it was small and crowded and add to that the fact mother was a horder.
Husband and I bought house next door to us, remodeled it, mother and sister moved in with understanding sister would get loan after 3 yrs. and buy house. We were not going to charge her anything only that she get a loan for the same amount we had on the house. At the end of 3 yrs. had to force her to get the loan. Then she became responsible for upkeep of house, payments etc. etc.
We helped in everyway we possibly could except for moving in with them but the complaining never stopped from my sister. It was always I can't do this, I can't do that, blah blah blah.
Then mother fell and broke hip and from that day forward really couldn't do anything. THen my sister really got angry. I tried everything I knew to do. I took meals to them, cleaned their house, bathed mother, did her hair every week, worked out a system with other sibs and sister's children to take turns at night, was always available if my sister wanted to go anywhere. Nothing helped.
I realize now that she was getting burn out but so was I - only not from mother but from dealing with her. Sister would never directly tell mother that any thing was wrong - she would make smart and hateful remarks to mother.
Then mother started having falls. She fell 8 times in 6 months. When she fell my sister would not call 911 - she said "mother won't let me". The morning mother fell into the bathtub at 4:30 a.m. my sister finally called me at 6:30. I called 911.
My sister quit taking vacatons, quit taking time to go to her children's houses and basically just worked and went home. Even though I tried to get her to go with me to my house in FL like we had always done in the past she said she couldn't. I even worked out for our children and my husband to take care of mother if she went on vacation with me but she said they couldn't do it. These children are all in their late 30's to early 40's I felt like they were capable adults.
Anyway, in Dec. 2010 mother had an episode of not being able to stand up, not being able to control her bladder. It had been going on all night and my sister finally called me at 5:30 a.m. Again, I called 911 and this time insisted she be taken to an emergency room. As we were leaving the house mother said "I'll never get to come home again". That was true because when we got to the hospital I begged the doctor to request nursing home placement for her.
To shorten the story it worked and mother was placed in a very good local nursing home and has been there for 1 1/2 yrs. Do you think this has helped my sister - NO. She still blames all of her troubles on mother. Constantly complains about mother and relives our childhood of how she had to do everything starting when she was 5 yrs. old. I know she had a hard life but I grew up in the same house and experienced everything she did. Mother was not mean or anything she just wasn't a loving person. She always put her needs above ours.
After mother went into the nursing home I visited her on Sunday afternoons and picked up her laundry. The following Sunday when I visited again I would take her laundry back. After about 3-4 months I started taking mother out on Sunday afternoons and then started bringing her to my house. My sister volunteered and asked that mother come to her house every other Sunday, then she insisted she do mother's laundry. (I need to insert that my husband is a double transplant patient and is disabled.) Except for complaining by my sister all went well until 2 weeks ago. My sister got mad at me, said she was tired of mother taking up her weekends and it had to stop. I said ok, give me two weeks and then I can take care of that. We ended up having a shouting match in which she said it was all my fault and that I never did anything to help her with mother.

All I want to do is leave town - that is not an option at least until next year when I can retire.

Any suggestions I'll take into consideration.