I may be wrong, but it is my understanding that league rules require cooperation with investigations. Obviously, if this were a criminal case, Brady wouldn’t have to cooperate, and they couldn’t punish him based on a civil-case burden of proof. But it’s not a criminal case. Whatever the rules are, Brady agreed to them. If the rules in fact required Brady to turn over the texts/phone, I’d give him a longer suspension, but indicate that the league may reduce it if he provides the texts/phone now and they exonerate him. Which they likely won’t. Makes Brady look worse, but that’s what he gets for not cooperating.
The rules are ambiguous as to what length he has to go to to cooperate. On the other hand, if he turns them over, they can do whatever they want with them...like selectively leak them, or release personal communication with his mother...like they did with McNallys texts.