Thank you for your follow-up. My apologies, I read the question as "supervised probation" and as such my answer will now slightly change.
Under NC law, if your boyfriend did violate his probation, he will get a letter in the mail within 10 days of the violation scheduling a hearing with the judge--there will not be an arrest warrant set out against him.
This is the NC code that governs:
(b1) Service of Notice of Hearing on Violation of Unsupervised Probation.
(1) Notice of a hearing in response to a violation of unsupervised probation shall be given either by personal delivery to the person to be notified or by depositing the notice in the United States mail in an envelope with postage prepaid, addressed to the person at the last known address available to the preparer of the notice and reasonably believed to provide actual notice to the offender. The notice shall be mailed at least 10 days prior to any hearing and shall state the nature of the violation.
(2) If notice is given by depositing the notice in the United States mail, pursuant to subdivision (1) of this subsection, and the defendant does not appear at the hearing, the court may do either of the following:
a. Terminate the probation and enter appropriate orders for the enforcement of any outstanding monetary obligations as otherwise provided by law.
b. Provide for other notice to the person as authorized by this Chapter for further proceedings and action authorized by Article 82 of Chapter 15A of the General Statutes for a violation of a condition of probation.
If the person is present at the hearing, the court may take any further action authorized by Article 82 of Chapter 15A of the General Statutes for a violation of a condition of probation.