Assuming her phone is configured to cloak the number in favor of the name, maybe you could grab her phone when she's asleep and swap the phone number for the scammer's contact with the number of your brand new burner phone from which you will impersonate the scammer from now on.

You could also record a video on your own phone as you swipe down through the scammer's texts as a crude way to archive them to study later so you get the impersonation right.