You are joking right?
Brady asked him to be there. He said NO. (The flight landed in time by the way)
Brady asked him to testify by phone. He said NO.
Brady is fighting for his reputation and the owner of the team, you know, the one who accepted the penalties, causing many people to think that was an admission of guilt, REFUSED to testify.
Kraft was asked to testify to show support. He declined to show that support, completing the slapping in the face of accepting the penalties in a speech that never mentioned Brady's name, answering the question of whether he hoped Brady would be there opening day by saying he 'hopes everyone who deserves to be there is' and then by abandoning him when he requested Kraft to be a character witness.
How would that have made a difference? It would have made a world of difference. As I sit here I see Kraft going out of his way to not support Brady.