A year ago I promoted the idea among my wife's family that we should establish a sign/countersign system for the family and use it regularly so that in the event of something like this we could positively identify a legit request.

Would have come in handy when our niece was traveling in Asia and asked for money a few times, but in this case it wasn't a scam.

I got no traction with it, which I was a bit surprised by because one of the family members works at the Puzzle Palace.