Depends. Some DUI's just get ~6 months probation, some get 30 days in jail + probation. It depends on how well they do while taking their test about their alcohol use and their attitude. Tell your friend that he/she should NOT say they party and drink quite often. They will be looked upon as an alcoholic and will get a tougher sentence.
At least until you sober up, and until you post your bail. If you don't post bail, you stay in until they release you because they need more room, or until your sentencing.
