My sister thinks nothing of making decisions on how Mom will be taken care of and then assigning me my part or cost. She has chosen to take care of Mom, won't even think of NH care. Seems like everyone (her husband/daughter) is just suppose to fall in line and do what she decides. If I disagree, then its FOG--fear, obligation and guilt laid on real heavy.
Breakfast (11 am) is a combo of Mom toasting her bread, fixing her coffee and maybe Sis suggesting some type of fruit. No lunch.
Don't handle day to day personal care which takes up time.
Mom can't be left alone for any length of time so Sis can't do much spontaneously.
But I have been driving (30 min each way) out twice a week for over 10 yrs It seems endless. I know it isn't what my sister does, but I would never do that kind of caregiving with Mother.
Having said that, and I do believe it, I'd also encourage you to do what you can to contribute to your mother's well-being and comfort. Just because your sister is going about this all wrong is no reason to hold that against your mother.
Many caregivers on this site post their dissatisfaction with how little help they get from their siblings. I feel strongly that each family member gets to make their own decisions about how much and how they will participate in the care of parents. But to not do your best for Mom because Sis is a tyrant isn't a good practice, either.
Make up your own mind for your own reasons. Don't refuse to do something just because it was Sis's idea, please, but don't let her guilt you into doing what you have chosen not to.