It is not my nature in a way, but I AM a rule follower. Could not think of ANY creative way for the sibling to stay in the home other than said sibling buying everyone else out, but it would be a huge burden.
I don’t like that you were forced into this very difficult situation.
If the stress is too much for you, you can bail...just keep that in mind.
Consider this:
The will could have stipulated that the caretaker sibling be given the house / some property / etc. after death of parent.
But it did not.
Ergo, this burden is not yours, and to be honest, made up on your part (out of good will).
Sorry for your loss, and good luck sorting this out.
If you cannot come up with more solutions than this, they you are way over your head. Best get some legal advise and use the rest of your family as sounding board. Do not do this in a vacuum.
You could divide the land into parcels to sell and keep the house as long as your sibling needs it.