Get involved again? Be part of the Care Team without any actual authority?

I should go, if only to make absolutely sure that the option of BeattyCare stays OFF the table. If your father attends this meeting alone then, even if he doesn't actually voice the thought, the thought that "it's okay, we'll have help (from you!), we'll manage somehow" will be running through his head and influencing his input to the plan.

You will also have the opportunity to run through your earlier suggestions and review progress on those.

Your role at the meeting is to keep everyone's mind concentrated on supporting your sister's function as an autonomous, independent adult as far as possible. Which means that NOT taking on responsibilities becomes your job. Will looking at it this way make it easier to see yourself as your sister's best and truest champion, instead of as a hard-nosed b-one-tch who doesn't want to know?

I agree with CM. Go, because if you're not there, you run the risk of Dad and Sis saying "Oh, Beatty will do THAT!"

Make it clear to the agency that you are there as an advocate and not a planner or do-er.

You could go, but not stay for the whole meeting. Can you invent some important appointment (emergency dental crisis, whatever) that would allow you to escape after stating firmly, “ whatever you all concoct, do NOT factor me in”? The “brilliant unmeshing” (wonderful phrase!) is GOLD in your life right now, so don’t even think about getting “enmeshed” again! Not your circus, not your monkeys.

Are you talking about your mother's or your sister's care because your profile says you are (were?) caring for both of them? Who is her in "her corner"?

Where is this care meeting taking place?
Who invited you to the meeting?

Your profile also says that you got off the bus. You could go to the meeting to make sure that you stay off the bus. You also could write a letter and send it Priority Mail to where the care meeting is taking place addressed to the person who invited you to the meeting clearly stating that you are off the bus.

When I'm conflicted about getting involved, I ask myself: "If I were the care receiver and the quality of my care/life was utterly dependent upon the informed/right/wise decisions & actions of others, what would I want someone with influence to do on my behalf?" This is not guilt, but a moral filter for myself. Your decision seems affected by the messy history the care. I wish you clarity and peace in whatever you choose to do.

I think you may want to bring your profile up to date. Its hard to look back on previous posts at this time.

I will assume you mean your sister. Does Dad have POA for her. If not, anybody?

I would be there to support Dad. Making it clear that you have no authority to make decisions. I went with Mom to doctor visits because she misinterpreted what the doctors said. Keep notes. Make sure Dad understands what is being said. Let the "powers that be" take over sister's care.

You can be supportive without taking on responsibility. If asked to, say sorry, I have a family that needs me and caring for my sister is a job on its own meaning my family suffers. Don't get bullied into something you don't want to do, it doesn't work out well. Go with those feelings. They r usually right. ☺

See, there's the thing, Beatty. Likely dad and/or Sis are mis-representing the level of support available, either from embarresment, confusion or...whatever. YOU need to be there in person so say "H double hockeysticks --"NO" I won't be doing THAT!"

You say you wish not to go. Then I think that you should not go.
I would explain to your father that you are currently not involved in care plans for your Mom, so you will not attend UNLESS he wishes you to.
IF your Dad says he would like you to attend, then I feel it would be the decent thing to do for him and for your Mom.
IF I went I would ask to speak briefly. I would say "Currently I am not involved in any decision making or care plans for my Mom, but Dad asked me to attend; so here I am. Dad, if you would like my input on anything, I'm here. Just ask me. I understand that the decisions are yours to make. I will try to give my opinion and then let you make the decision." I would then tell the careplanners "I will let you know only if it is suggested that I can provide care in the future that I may not be able to".
If you aren't strong enough to do it in that way my advice is to NOT attend at all. It is a simply thing to say to Mom "Dad and you will be attending a plan for your future care. The decisions aren't mine to make; they are your decisions to make together. I will do all I can to honor those decisions with what time and care I can contribute." Big hug. Walk away and get a big coffee and a delicious sweet!
Good luck, hon. Whatever your decision hope you will let us know how it goes.

Hard to know how to advise. Need more information.

Given the past circumstances, it appears to be in YOUR best interest to be at this meeting. To make it crystal clear to all involved that you are now and never will be a part of the care team for any of them — sister, mother, or father. I know it sounds harsh; it is called self-preservation.