I'd tell them what I tell most customers: If you've got something really, really important on your device - print it! We still have the Book of Kells and the Magna Carta. How many jpegs or mp3s do you reckon will still be about in a thousand years time?
That's a few steps ahead of them.... we are still trying to get a couple years of texts onto a computer so we can at least have them in a format we can manage...
OK - well, quick and easy: Copy/paste the text into an email, and send it to them. Then copy into Word or whatever and do your layout stuff there. Not hugely familiar with IPhones, but I assume this would be possible...
Pretty much any IOS data recovery program will do that. Use one years ago but don't remember the name. If it's that important then they'd better have backed up the iPhone as well. EaseUS has a free one. But if they have not updated the IOS in a while you might have a hard time.
Syncios has some free tools.
My clients use what I use - JottaCloud - on Android and iOS devices as well as their PC's.
SMS are backed up instantly from devices.