That does not matter, his parents were not there of their on volition but under orders. Like diplomats their children are NBC both from a practical view and a moral view. It was never the Founders intention to exclude children of those doing the nation’s bidding. That would inhibit people volunteering for such duty. NBC is the same concept as that making the King’s subjects born abroad to subjects serving the King.
Morally it would be highly unfair and not reflective of the desires of the Founders. These children were not intended to be excluded.
This was discussed ad infintum years ago. He’s not a NBC, whatever beliefs or opinions about “fairness” anyone has.