If they're released under supervision, the mental health team and the releasing institution communicate with the release destination. Appointments are set up. Sometimes the offender is even accompanied from the institution to the community so that there's good communication between the staff who are receiving him and the staff who are delivering him, so to speak. As long as he is getting released on supervision, that follow-up is there.
Evidence of meeting #18 for Public Safety and National Security in the 41st Parliament, 1st Session. (The original version is on Parliament’s site, as are the minutes.) The winning word was institutions.
A recording is available from Parliament.