The math does not quite line up, and it is worth investigating. Here is what the numbers should look like.
Three years at 50 percent means 18 months of actual time to serve. He was in custody from October 18, 2021 to his plea on December 20, 2021, which is about 63 days of pre-plea credit. Working from his plea date and subtracting that credit, the estimated release should land somewhere around early to mid 2023, not May 2025.
May 2025 is roughly 42 months from his arrest date, which is closer to a full 3-year sentence with no 50 percent reduction applied. That suggests one of a few things: the 50 percent reduction has not been factored into the DOC calculation yet, the plea agreement terms were interpreted differently by the court or the DOC, or there is an error in the system.
The state DOC website is generally reliable but not infallible. Calculation mistakes do happen, particularly when there is pre-trial time to credit and percentage reductions to apply.
The most direct way to resolve this is to have his attorney review the Judgment and Commitment Order and compare it against what the DOC is showing. The plea terms in the official order are the authoritative document. If there is a discrepancy, the attorney can file a motion to correct the record. Do not let a calculation error sit unchallenged.