He was picked up by the police when he was walking back to the dorm and was put in gaol after failing the breathalyser test - can we assume that because it is his first time he can plead guilty and be put on probation or should he get a lawyer?
Lawsuit / Dispute Attorney
To make sure all direct and collateral consequences are known to you and your son, you may consider to hire an attorney. If this is handled wrong, your son's college applications, job searches and bank loans in the future can be messed up.
You can miss and say the wrong things if you are not represented by an advocate as your attorney.
You might find my Legal Guide helpful "Ethics: Yes I Need a Lawyer!"
You might find my Legal Guide helpful "How to Choose A Lawyer For You."
You might read my Legal Guide "Can An Attorney Really Help?"
Ask yourself, do I really want to go it alone?
The Judge Cannot Help You
Remember, if you represent yourself the same standard as a professional attorney is applied to you. The Judge cannot give you assistance and maintain the required courtroom decorum of being fair and impartial to both sides.
All Rules Apply Equally To You
As pro se, you'll be held accountable for having the same information about the rules of court, rules of law, and rules of evidence as an attorney who has years of experience handling cases. The judge would be right not to give you any breaks. If you file a brief or motion to dismiss incorrectly without following either or both of the procedural or substantive rules it can and most likely will get thrown out of court.
What You Do (Or Don't Do) Can Mess Up Your Appeal Rights
If your case ends up going south with you losing you cannot appeal based on not having had done things as well as an attorney. Every Judge I know warns pro se parties that representing themselves is not a good idea. The judges have a reason for doing this; IT IS A TERRIBLE IDEA
Good luck to you.
NOTE: This answer is made available by the out-of-state lawyer for educational purposes only and is not like communication with a lawyer with whom you have an attorney client relationship along with all the privileges that relationship provides There is no attorney client privilege between you and the attorney responding.
Criminal Defense Attorney
Assuming the evidence is sufficient and also assuming that there are no defenses, probation will include a minimum of 50 hours of community service and possible loss of driving privilges for up to 12 months, in addition to random drug and alcohol screens. A skilled attorney may be able to minimize the probation requirement and save the driving privilege. Recommend you seek representation.