Not sure what you are asking. Any conviction or ARD disposition for a dui within the past 10 years counts as a prior offense. You should contact a criminal defense attorney to review your specific situation.
You should contact an criminal defense attorney to explore the facts of your case, evaluate your options and get an explanation of the potential ramifications of pleading guilty. Most offer a no charge consultation. Good luck.
The state can charge you under subsection a1, in the officer's opinion you were under the influence to a degree that rendered you incapable of safe driving. Get a qualified attorney to review your case and your options
The summons usually states first offense, even when it is not. Your prior offense will likely show up and this will be treated as a second offense. Nonetheless, you need to consult with a qualified attorney to make sure your rights are protected and that you know all of your options.
Can he be charged? Yes. There may well be a number of defenses available if he is charged. The police need to establish his BAC within 2 hours of driving. From your facts it's hard to tell when the accident occurred or who could establish such time. Also there may have been alcohol consumed after the driving but before the BAC testing. You should consult with a qualified criminal defense attorney to make sure your rights are protected.