Brady in a no win situation with the phone. If he keeps the phone and refuses to turn it over and gets rid of it because it is broken, people will say he is hiding something and destroyed the evidence (which is what is happening).
If he hands over his phone and Wells finds nothing, people will say that he deleted anything relevant before handing it over and so he is hiding something.
The phone is irrelevant because text messages/emails can be deleted from the phone so if he handed it over, there is no way to find out if messages were deleted except to contact the carrier (which is what Brady did). No win for Brady with the phone.