take the sight off the bow, put him 5 feet in front of the target with eyes close make him darw don't let him put his finger on the trigger, a somepoint you trip the release for him. then have him shoot with eyes closed.

don't let him move back until he can release without flinching. then you can start up close to release while aiming with the sight and work your way back.

at least that's what I did to get over the it..

I do a lot of shooting up close to pratice releasing while aiming now. Good luck..