[cypher]

If you have a photo of his cage set up that might help us see if there is anything you could change there that might help.
I agree with CMB that it might be worth trying to handle him out of the cage, it sounds more like just fear than aggression but as long as he's in a safe place where you can sit with him, a playpen is ideal, it may be worth a try.
It's never too late to go back to basics, do the tissue trick, just talk to him quietly without interacting any more than that for a few days then gradually reintroduce your hand with a treat & try to slowly build up his confidence.
Is there anything in his environment that might make him nervous, other animals for example or a lot of people or noise around?