What is the maximum jail time someone could serve for violating (drug weed charge) a felony probation in NJ?

Basically we were voilated for a drug charge that he finished probation with and did not complete the fine. He was caught with drugs again. :(

He will attend a probation violating hearing at which time the original sentencing judge will decide if he will have his probation revoked and have to serve his original jail time.