I have a relative who did not complete Army bootcamp. What's the definitive source (US Code, USMJ, etc.) that states he is NOT a veteran?

This thing called google is about as reliable as fox guarding the henhouse. What is the federal law they reference ? Bet you can't find one that uses those words.

SP5 Peter Keane since you asked...

SFC (Join to see) - (18) The term “discharge or release” includes (A) retirement from the active military, naval, or air service, and (B) the satisfactory completion of the period of active military, naval, or air service for which a person was obligated at the time of entry into such service in the case of a person who, due to enlistment or reenlistment, was not awarded a discharge or release from such period of service at the time of such completion thereof and who, at such time, would otherwise have been eligible for the award of a discharge or release under conditions other than dishonorable

SP5 Peter Keane the point is that the guy didn't even bother to look. In fact, if you click on the link, all that information is included. But, it answered his question:Which USC? The answer is title 38.