If he has violated his probation in New York, he can be taken back before the New York court over the probation violation. The longer this person waits to report the violation, the less likely it is that action will be taken. But we don't know the context, so we can only guess. If he wants advice as to his probation violation, he should consult a criminal defense lawyer so he can discuss the full details of his conviction, sentence, and the violation in confidence.