It’s the same on the 6.
I’m a little too clumsy on the phone to take advantage of this feature to take good spontaneous photos, though. Still really need several seconds notice.
So basically, she’d like to use her iPhone 6 almost as a body security camera where she can shoot a video in emergency conditions without worrying about it turning off before she is done.
Your friend needs to be more specific, and walk through what her issue is, and what she thinks the solution is. Because currently, she’s describing the normal iPhone camera app. The video doesn’t turn off until you tell it to (click the home button or a volume button) or it runs out of storage.
I’d find out how much storage she has left on the phone. Not how much storage the phone has - how much is available. (i.e. Does she have 3000 pictures she needs to transfer to a more permanent storage solution?) And then find out if there’s user interface issue with the current iPhone camera app where she’s inadvertently stopping a video before she’s done.
Because a 3rd party app isn’t going to fix the fact that she needs to clean out her phone, but it could be a solution to a clumsy interface.