He was convictred in a military court of violating a lawful order. (In fact, he pleaded guilty to that charge.) So, barring a reversal on appeal (extremely unlikely given his guilty plea and his sworn admissions to the judge), it is now conclusively determined against him that he violated lawful orders. So he was injured not by Obama's failure to answer questions, but by his own admitted criminal acts. See, for example, the Supreme Court's decision in Heck v. Humphrey (1994) (unreversed criminal conviction bars any civil suit for damages based on that claim that that conviction was wrongful).
He plead guilty to four specifications on charge No. II, but not guilty to charge No. I. He was not allowed to challenge the lawfulness of his orders, so there are different issues he could file suit over.