You should contact/hire a Criminal defense attorney ASAP, and do not post any more admissions/confession in this public forum for your prosecutor to read.
Ms. Holton gave prudent advice -- you need a criminal defense attorney and need to understand that there is no privacy regarding things you post on a public forum such as this website!!
In no way am I offering you legal advice, and in no way has my comment created an attorney-client relationship. You are not to rely upon my note above in any way, but insted need to sit down with counsel and share all relevant facts before receiving fully-informed legal advice. If you want to be completely sure of your rights, you must sit down with an experienced criminal defense attorney to be fully aware of your rights.
Your significant other needs to contact his previous attorney for the DUI to get some detailed advice. If he never hired an attorney, it sounds like now is the time for you to do this. At a minimum aside from getting counsel hired, he needs to get a chemical use assessment and follow its recommendations regarding any classes, counseling or treatment.