The inmate always knows their out-date - your brother knows for sure. You can also call the facility and ask to speak to his counselor or case manager. You might find the information online; if he is in federal for sure, and most of the state websites have their release date.
https://www.inmateaid.com/ask-the-inmate/how-do-i-find-out-my-brothers-release-parole-date#answer
Accepted Answer Date Created: February 15,2016