[USA] How do I successfully convince a family member I care about they are (most likely) in a Ponzi scheme?

A family member threw 35k (I think life savings left) in what seems like a “get rich quick” investment club through a “friend”. Their account showed 81k after just two weeks of investing, mind you they are in their late 70s – not the time to be investing in high risk accounts. I’m already frustrated and brought my concerns up, any thoughts on how to provide proof and try to save whatever money is salvageable? With the micro chance that it is a legitimate investment club. I care deeply for their future but it might be futile.

“Bull Trade Club” for context.