If it’s not in you to speak up directly to them, enough to turn them from this scheme,( and you’re clearly not, or you would have before now), then I would send a couple of anonymous letters to ticket purchasers and stand back and watch their scheme unravel.
They won’t get into any trouble, as they are still in a position to reverse the wrong by returning the ticket price, I believe.
The letter should be carefully worded to indicate that your Mom’s illness has produced a change of character in her, so people will be somewhat understanding and forgiving, while refusing to participate.
It’s a fundraiser to try to raise funds to hire a big burly man to punch you in the stomach when you are constipated to help you start to eliminate again.