How does family inform loved one need for being placed into facility?

I don't know if you need to tell your sibling or your parents the need for a facility, but in either scenario, tell whomever it is that you want the best care for them and sometimes the best care is not at home.

You cannot decide for your sibling what she must do. You can tell her that you feel that the care of your Mom and Dad are now too much, and that she should reallly consider placement now in long term care. That she has been heroic in her doing this but that human limitations are a fact. You can tell her you cannot be more help to her living away as you do, and it breaks your heart to see her in this amount of stress. Ask her to think, now covid is over as a concern for vaccinated seniors, of placing your Mom and Dad. If you are able to offer this, tell her you will come to help her explore options for them
If this sibling will not listen to you then you will have done what you are able to do in the situation. I am so sorry. This has to make you feel truly helpless.

Tell them with love that you appreciate their caregiving but it is best for everyone, especially your loved one to be placed in a suitable facility. Say, that you and she can be advocates for your loved one while in the facility.

Best wishes to your family.