Can a DUI and possession charge be cleared from a criminal record?

Everyone makes mistakes and they are not always fatal.  Making them at 18 makes them more than likely to be "forgiven" for lack of a better word, depending on what they are. Now, he was just arrested, correct?  Then I would suggest that the best investment you make in his future is to hire a very good attorney NOW to help.  You need to see what the actual disposition of the case will be and how you can help sway the outcome with getting him in to a voluntary program for drinking and driving now before a judge orders it to show that he has every intention of it never happening again, etc.  As for Expungement of his record, discuss it with his attorney (remember that the arrest has to be expunged separately).  How you plead matters!  Here is the law:

"O.C.G.A. § 35-3-37(d) (1) allows for the expungement of arrest charges by a local law enforcement agency when certain conditions are met (as outlined in this statute). If approved by appropriate prosecutor, the arrest cycle is sealed on the Georgia criminal history report by GCIC. Access to that arrest information is restricted to criminal justice agencies only.The following are examples of final court dispositions that may qualify: Dismissed: Not Presented to Grand Jury: No Further Action Anticipated; Nolle Prossed/Prosequi; Dead Docket; or No Record on File. Dispositions of Guilty, Not Guilty, Nolo Contendre, and First Offender Act are not eligible. "  Good luck!