Attendance at substance abuse programs is generally not mandatory, but it is strongly encouraged and in some cases tied to parole eligibility or sentence reduction benefits in ways that make participation effectively necessary for anyone who wants to get out at the earliest opportunity.
Alcoholics Anonymous and Narcotics Anonymous meetings are available at virtually every correctional facility in the country. They are volunteer-driven programs where outside members come into the facility to run meetings, which means they operate at a remarkably wide range of institutions including smaller county jails. For someone serving time for repeat drunk driving offenses, these meetings are almost always going to be recommended by the case manager or counselor as part of their programming plan.
Beyond AA and NA, many facilities offer structured substance abuse treatment courses, cognitive behavioral therapy groups, and in the federal system the full RDAP residential treatment program for eligible inmates. For a repeat DUI offender, demonstrating active engagement with alcohol treatment programming is one of the strongest arguments that can be made at a parole hearing. Boards look for evidence that the underlying issue is being addressed, not just that time is being served.
Individual counseling is also available at most facilities, though the depth and frequency varies significantly depending on the institution's resources and staffing. Larger state and federal facilities tend to have more robust mental health and counseling services than smaller county jails.
The programs are there. Taking advantage of them is the smartest thing a repeat DUI offender can do for their record, their hearing, and their life after release.