Numberlock, best wishes to you and your family. I like the Irish approach of seeing a wake as a form of celebration. You lost much of the real mother a long time ago and now is a chance to both mourn the person she was and celebrate her life.
WBN. Your journey over the past few months has been extra-ordinary. I think your friend is right and suspect the events of the last few months have helped you gain a perspective on your family relationships and on your parent's divorce. Counselling sounds like a good idea and should help you make sense of it all and to move on.
A lot of the stress will have come from the fact that though you have assessed the problem and found an acceptable solution, you have not had sufficient control to move from one to the other. Your brother clearly needs to control. It is unacceptable that he does so and could then expect you to run round and prop up an unsustainable solution. She may have capacity now after a couple of months of good consistent care and company, but may not when back on her own. And at some point, whether it is a month, three months or a year, certainly wont. What happens then. Unless he agrees (and he will be on the other side of the world, with no good feedback on what is going on, and presumably reluctant to lose face) you wont step in and I assume Social Services will feel the same.
I would be tempted to ask Social Services, the panel, your brother's lawyer etc, how they see things evolving going forward as she (inevitably) loses more capacity. There needs to be a process whereby decisions can be made in a straight forward and sensible way if she is unsafe, unhappy or being home on her own is giving her a significantly reduced quality of life.
I assume that with the earlier planned panel cancelled your brother is aiming for some form of emergency order to get her where she says she wants to be. I also assume that her motivation in insisting she goes home is that this way she gets to see the son she has not seen for five years. (My mother still says she wants to go home, as I don't think she can deal with the finality of giving up her independent life, but happily agrees it is a good idea to stay where she is "through the Winter".)