I think you need to try to work on gaining his trust again. Obviously this poor bird has gone through some very frightening moments that I doubt he will ever forget in his lifetime.

I suggest that you spend time with him every single day. Sit by his cage and talk to him gently. Talk to him with your hand in the cage. Don't try to touch him. Let him learn to trust your hand. If you touch him, he may think your hand is evil and will lose trust even more. Keep your hand in the cage and talk to him 2-3 times a day for 10-20 minutes each time. After a week, put your hand in the cage as you did before except this time have a piece of spray millet in your hand. Hopefully this will tempt him to come to your hand. Do this every day for the whole next week. Once he gets used to your hand in the cage with food, VERY slowly, and gently, try to slide your hand under his feet. Make sure no other pets are around at this time. Once he gets on, talk to him with your hand still in the cage, with the bird on it. After 3 days of doing this, take your hand out with your bird on your hand. (Be sure to have his wings clipped before). Once he gains confidence and stays on your hand, just spend more time with him everyday. I hope he'll gain confidence in you again and become the sweet tiel he was before the tragic incidence.