This person is a US citizen. What happens if he just said nothing (beyond identifying and answering basic questions) and refused to cooperate? How long could they hold him? As a citizen they have to allow him to enter eventually.

According to the ACLU I think this person would have been better off saying little and not wiping their phone.

https://www.aclu.org/know-your-rights/what-do-when-encounter...

And they would have taken his phone, pulled it apart and cloned the memory to get the data. And in a month or three, returned his phone to him in some condition which may or may not include "working".