In Georgia your license is never automatically reinstated. He will have to go to the DDS and reinstate. He will have to provide proof of the clinical evaluation and treatment and the DUI School. He will also have to pay a reinstatement fee.
If you are on probation in another county, your probation officer will only find out if you tell him / or her or if they run your criminal history. Many probation officers will run the history every few months. As a result, you do have a chance of being caught. The problem you have is the failure to report the arrest is a further violation of probation. You could face additional consequences for failure to report the arrest. As a result, it is a difficult choice to report the arrest of...
It may be worth attending court. You can then ask for the speed to be reduced to 14 over. With 14 over, you will receive no points on your license. In fact, the ticket would not even be sent into the State.
Legally he is required to notify his probation officer of any arrest. The choice to do so is always a difficult decision. It is possible the probation officer will never find out, and he will not face revocation. However, if the probation officer does find out (and he does not inform him), failure to report the arrest will result in an additional violation of probation.
Being on probation creates a very difficult decision because legally you are required to report any arrest to the probation officer. Yet, by reporting the violation, he is risking a revocation of his probation and loss of possible first offender treatment if he has first offender. Seek the advise of an attorney immediately.