Good time credit in Louisiana works similarly to most state systems but the specific impact on a release date depends heavily on the details of the sentence imposed and what conditions the judge included in the commitment order.
The standard good time reduction is 15%, meaning an inmate who maintains a clean disciplinary record throughout their sentence serves about 85% of the total time. That calculation applies automatically and does not require any special arrangement. On top of that baseline, Louisiana does have provisions for additional good time credits earned through work assignments, educational programming, and other approved activities, which can push the reduction beyond the standard 15% in some cases.
The larger variable is whether parole is written into the commitment order. If the sentencing judge included a parole provision, your boyfriend could be eligible for a parole hearing at a point well before the 85% calculation would produce a release. That hearing date and the parole board's decision would determine whether he gets out before 2020 through that route.
Cooperation with prosecutors is the other mechanism that can produce a more significant sentence reduction beyond what good time alone provides. If there was any agreement with the prosecution involving substantial assistance, the terms of that agreement and how they interact with the sentence are critical factors.
The most accurate answer comes from the commitment order and the facility's time computation sheet. Have your boyfriend ask his case manager at Collinston for the current calculation showing exactly how his credits are being applied and what the projected release date reflects. That document gives you a real number rather than an estimate.