The nice man cold calling here won't be a f*cking idiot so he won't try to get her to jump through a bunch of complicated technical hoops that will surely fail because your poor meemaw is not tech savy enough to pull it off, to turn on a buried setting then visit a sketchy website then download and locate a package then agree to the warning at the package install and he isn't an idiot and knows that so he will just tell meemaw he's from the bank and he needs her credentials and she'll turn them over or hang up the phone. That you think the App Store is protecting her bank account is effing laughable. Malware is the very last thing a baddie on the phone with your poor meemaw is going to try and you either know that and are feigning stupidity or the alternative.

https://imgs.xkcd.com/comics/security.png needs a companion for people like you who infantalize seniors (if they're 80, they were using Windows 7 at work before they retired) and make up hacker scenarios that would never happen to seniors to defend an indefensible position that is "I stan Apple, or possibly all multi-trillion dollar mega-corporations with walled gardens, because hacking is for losers and I'm here on a hacking forum to let everyone know that."