Sibling Is Facing Foreclosure, Frustrating Circumstances... How Should I Help?

Throwaway account. Genuinely, this is my sibling's situation, not mine. Much of the 'story' of this is what the sibling related to me. Sibling has had financial issues in the past. This may belong in r/FinancialAdvice, but I sense things may beyond money fixing...

Sibling is in Alabama, I am in Georgia.

Sibling is self employed in a profession that involves taking many direct payments, and uses Square to accept those payments. Sibling purchased a home in August of last year. They claim that they [attempted] to use Square to make the mortgage payments, however apparently the mortgage company never actually accepted them. Sibling and their spouse apparently ignored many letters before realizing the situation and were months past due. Between them and the mortgage company, it was finally realized the failure to make/accept via Square, so Sibling began the process of getting the money back from Square and succeeded.

Sibling apparently also banks with a non-mainstream online-only bank, so then getting the funds from Square to that bank was a process. The mortgage company apparently told Sibling that they HAD to overnight a cashiers at the time she was finally in possession of the funds. They get online bank to increase withdrawal/ATM limits, and over the course of several days they get the cash in hand... at this point I'm just going to round the amount to 15 thousand dollars.

Sibling takes cash to local, mainstream brick-and-mortar bank they have a car note with and get a cashiers check, takes that to FedEx, and send check and paperwork as instructed.

It takes two weeks for the mortgage company to come back and say "Got your FedEx envelop - and the paperwork - but no check." Commence cashiers check cancellation process... money is locked up for 90 days according to brick-and-mortar bank.

1-2 weeks later, the foreclosure notice is in the newspaper and they're getting notice of foreclosure. (Don't ask me what notices they've gotten or ignored, I'm aware these things don't happen overnight.) I would have thought all this is was a scam if I didn't find the notice in the newspaper myself.

Courthouse steps sale is in 10 days.

I am liquid enough to help my sibling - I've known about the situation for 48 hours at this point. After the initial story from my sibling, my spouse and I slept on the situation and decided that if there was something we could do, we should do it...

I asked sibling "If a wire or ACH could happen today, would it solve this problem." They waited until the end of the day to call/text me back (they were working, maybe I didn't imply strongly enough that I was willing to make a payment). That was Friday. Little/no contact since then from sibling.

So, I have two areas of questions:

1. What do you think the options for my siblings actually are at this point? The mortgage company has referred the whole thing to Brock and Scott for the foreclosure, and with them involved, it's not clear to me whether a payment is possible at this point, who it would be to, a deadline, etc... (Not that I'm trying to get directly involved). Apparently bankruptcy is an option to stop foreclosure? If the story is true, perhaps they could even exit bankruptcy before it's complete?

2. If I do help my sibling, are there logical safeguards I should put in place? Some form of written agreement? Do you have recommendations on how to go about this? I want to verify the status of the cashiers check cancellation and that that money IS coming back, and if possible or logical draw up an actual contract with my sibling about this (if that's a logical thing to do?)

I greatly appreciate any input you may have. (including if it is just a statement of direct advice to my sibling of 'Go get an attorney.')

I have redacted some known details or minutiae for the sake of length of this post. Happy to fill in any gaps I have knowledge of.