He is going back to Copiah County to stand in front of the judge who signed that warrant, and that conversation is not going to start from a friendly place.
Drug court is an alternative to incarceration specifically designed for people whose criminal behavior is driven by substance abuse. A judge who offered someone drug court was extending a significant act of trust, choosing treatment and supervision over a prison sentence. A warrant issued from that program three years later tells the judge that the trust was not honored, and three years of distance does not soften that message.
What happens at that hearing depends on several factors. The specific nature of the violation matters. Was it a failed drug test, a missed appointment, a new arrest, or complete absconding from the program? The more deliberate the noncompliance looks, the harsher the likely response. The judge will also consider what has happened in those three years. If your husband can demonstrate genuine change, employment, sobriety, family stability, an attorney can use that to argue for something short of the maximum consequence.
Without drug court leniency as an option this time around, the judge can impose whatever sentence was originally suspended when drug court was granted. That is the worst case scenario and it is on the table. Whether the judge goes there or finds a middle ground depends on the full picture presented at the hearing.
He needs an attorney in Copiah County before that hearing, someone who knows the court and the judge and can put the strongest possible case together. Walking in without representation at this stage is not advisable.