Training a model on sound data from readily available public social network posts and targeting their followers (which on say fb would include family and is full of "olds") isn't a very far fetched use-case for AI. I've created audio models used as audiobook narrators where you can trivially make a "frantic/panicked" voice clip saying "help it's [grandson], I'm in jail and need bail. Send money to [scammer]"

If it's not happening yet, it will...

It is happening already, recently Brazilian woman living in Italy was scammed thinking she was having an online relationship with Brazilian tiktoker, the scammers created a fake profile and were sending her audio messages with the voice of said tiktoker cloned via AI. She sent the scammers a lot of money for the wedding but when she arrived in Brazil discovered the con.

It's already happening in India. Voicefakes are working unnervingly well and it's amplified by the fact that old people who had very little exposure to tech have basically been handed a smart phone that has control of their pension fund money in an app.