The situations you are describing come under the authority of the Interstate Compact pertaining to the transfer of Supervision. Typically, this is initiated by the State where the person who is on release is currently supervised, who then contacts the State where you want to move. Unfortunately, the individual States can refuse to accept the transfer, and in our experience do when the person being supervised has never been a resident of that State. I suggest you need to tell the person who is being supervised to discuss this with his parole officer who can give him more specific information on how IL will want to proceed. Good luck.
This answer does not, nor is it intended to, create an attorney-client relationship; or, constitute either legal advice or attorney advertising. Rather, given the nature of this forum, it is offered solely for information purposes, as a starting point for you to use when speaking directly to a lawyer in your State. Do not assume that the legal conclusions I mention that pertain to NJ are applicable in your State. Since the facts of each case are different, it is critical for you to consult with qualified counsel with whom information can be shared and assessed under an attorney-client privilege, so that competent advice can be obtained on which you can make informed decisions. Contact an experienced criminal defense lawyer admitted to practice in your State before making any decisions about your case.