Speaking in his final England media conference, Stokes threw his "100% support" behind vice-captain Brook being his successor.
"There was a reason why he was asked to be vice-captain," said Stokes.
Brook has been deputy since the end of last summer but Joe Root was preferred when England needed a captain for the second Test against New Zealand, amid the investigation into the nightclub incident that ruled out Stokes.
It is six months since Brook's own late-night episode, when he was punched by a nightclub bouncer in Wellington the night before leading England in an ODI against New Zealand last November.
Key said it was not the "right time" for Brook to take on the job, even on an interim basis, earlier this month.
Stokes' backing of Brook, though, was absolute. Given the opportunity, he did not give such a strong defence of McCullum or Key, saying he does not have to make those decisions.
"You are asked to be a vice-captain for a reason," Stokes said. "It is a natural progression. I see no reason why Harry shouldn't be asked to do that.
"In the last couple of weeks there were some decisions that were made [about Root's appointment] but I wasn't part of making them."
Brook is set to speak to the media on Tuesday - the first time he will have spoken publicly since being overlooked for Root.
The quick turnaround also points to the difficulties Brook would face if named captain in all three formats.