This is a topic close to my heart. One of my first really difficult jobs in the strategic communications world was designing ways to encourage and support FARC rank-and-file soldiers in Colombia to demobilize. It’s very difficult to bring someone to the point of walking away from not just an ideology but a way of life and a safety net.
This article in the Harvard Business Review hits on some of the key strategies from allowing people with losing or discredited viewpoints to change their thought process without defensiveness or shame. How to Build an Exit Ramp for Trump Supporters