I'm guessing the case was dismissed at a probable cause hearing, which would not preclude a subsequent filing of a formal charge. Contact an attorney right away to discuss your god son's situation in detail.
Rather than ask this question on an open forum site, why don't you call several attorneys directly and meet with them for initial consultations? That way, you can get a fee quote based on the unique circumstances of your case.
Have you met face to face with any lawyers? I suggest you start there, as many of us will meet with you for a free consultation. And, you'll likely find someone with the experience to handle your friend's case for a reasonable fee.
This arrest could trigger a probation violation, and will subject you to harsh sentencing provisions and severe license consequences. You need to consult with several lawyers, and hire an experienced attorney as soon as possible.
If your second arrest resulted in a DUI conviction, then the first case will be handled as a 2nd in 10 year offense, which means a higher fine, more community service, and a lengthier jail sentence. Also, serious license implications. If you currently do not have counsel, I suggest you get an attorney right away.
Your case involves many issues, aside from the DUI charge and license consequences. Given your age, you need to make sure you have experienced counsel to contest these charges. Speak with several attorneys, and hire one soon.