The question of what a person can expect to happen when he/she is arrested and/or charged with driving under the influence must be answered by first stating that every case is unique. The process and potential outcome of a given case will be affected by several factors including, but not limited to, the county or city of arrest and or charge, the prosecutors involved, the history of the defendant, whether there was an accident or not, the level of the breath or blood test, and the current state of the laws. What happened in your friend's case in city X on date Y before Judge Z will not tell you much about what will happen in your matter.
That being said, if a person is charged with DUI/DWI the prosecutor will file a document called a "compliant" in the applicable court. The court staff will schedule an "arraignment". At the arraignment, the person will be formally charged and the judge will imposed conditions of conduct while the case is pending. This might be bail, a monitoring device, an ignition interlock device, prohibitions on certain activities, or a simple promise to appear in court when summoned. The case will then move into a pretrial status. During this period, the now "defendant's" attorney and the prosecutor will exchange information, negotiate and conduct their respective investigation. There may be one or a number pretrial hearings that are generally held once a month. If the case is not resolved during the pretrial period, it will move into a jury trial track in which the parties will prepare to have the case heard before a jury. This does not preclude further negotiations or settlement, but moves the case along if prior negotiations were unsuccessful.. A jury trial will usually be the determinative hearing in a case, absent a conviction, successful appear, and retrial.