Power of Attorney property question

[TheVanguardSix]

Reaching out to MN brains that work better than mine with gratitude in advance.
I suddenly feel a bit concerned about the fact that my home- mid-divorce- will eventually be sold (that's fine) but my STBX's sister is his Power of Attorney who will be dealing with his financial stuff on his behalf (he's in prison).
What pitfalls should I be aware of?
Background: We're still working out a fair split and won't sell until next Spring/Summer, but I will be dealing with the selling of our family home myself. His sister is in Australia, we are on very poor terms, don't speak, no respect for one another, and really, I don't think we'll ever be able to be in the same room together (she supported her brother unwaveringly throughout his criminal proceedings and encouraged him to lie and minimise his crimes against our daughter, so there is no coming back from that in all honesty).
I suppose I'm wondering if I need to worry about her dealing with the sale as his POA while he is in prison. He can sign documents and his mental capacity is totally fine. I just feel uneasy and I'm hoping the wisdom of MNers can calm me down a bit.

I don't know for sure, but as I've just been dealing with my father's POA (he had a stroke, needs 24/7 care, loss of mobility and speech but full mental capacity) as long as he has mental capacity the POA doesn't get invoked?

If your ex has capacity he won't need his sister to act as POA in this instance, he will still receive all legal documents and be able to seek legal counsel for this matter, it will just be sent to/received at the prison. At least that's my layperson take on it.

I agree with maydaze
As long as he has capacity the Poa doesn't come in to play

The financial PoA can come into operation before the donor loses capacity, it all depends on how it was worded. They are not just for loss of capacity but also for situations like this one where the donor cannot undertake their daily business. Deployed military personal, arctic explorers, astronauts - they all have capacity but aren't in a position to phone the bank.

The health and welfare PoA only comes into play on loss of capacity, the finance one depends on how it was filled in. If STBX knew he was facing prison he will have written it so it can be used immediately, otherwise there's no point having it.

Personnel even

Thank you so, so much Knotaknitter, FredaFox, and MayDaze for your incredibly helpful replies.
I suppose I'll have to ask his solicitors about the wording (if I'm even allowed to ask- perhaps that's overstepping boundaries). I guess my main worry would be that it complicates not so much the division of assets but accessing the proceeds from the sale of our home. And I suppose his solitors can clarify that.
I'm self representing so don't have my own solicitor to turn to for concerns like this one. So I'm really grateful for your input.

The way we use dad's POA is to be his voice, so any communication between him and the bank or his pension (for example) can legally be handled by us (we had to register it and provide proof via the gov website) but he still makes his own decisions so we can only act on those decisions.

So in your case (from what pp said) the sister could interact with his solicitors but only on his instruction, she couldn't just decide eg to refuse a settlement off her own back .