I am so sorry that you are freaking out right now...
Lets do a reality check. Dont know your story but from what I read maybe your son will actually learn from this and realize that this is his last shot. I can empathize and understand kinda how you feel but this is apart of his process that he needs to go through. He was caught. That is a good thing. He is facing a HUGE consequence. That is even better. And now as hard as it is you need to stand back and let him fall...
Remember the poem "Let Me Fall". Read that over and over so that you can stop freaking out. Say a prayer and give it to GOD. This is all apart of his plan.....
My prayers for you and your son....This may turn out to be the BEST thing that EVER happens for him in his journey of sobriety.....