Poor baby. He might have a concussion, so keep him in a semi-dark spot as heat and light can make things worse. You can gently dip the tip of his beak (not over the nostrils) in a small bowl of water. Remove the bowl in front of him, he might drown if he tries to walk and fall over. What do the droppings look like? If brown and firm, then he was recently fed. In this case, just keep him hydrated for now.
If droppings are green and creamy and very little, then he needs to be handfed. Defrosted green peas works best. Just put him on your lap (facing to the right if you are righthanded). Reach with your lefthand over his body and head and open the beak with those fingers. Have a pea ready in your righthand and put deep inside his beak over the tongue. He will need 90 peas per day divided into 3 meals of 30 each. Start by feeding him 10, when that gets digested you can feed more.
Glad to hear he is doing well. He will benefit from calcium with added Vit D3 and a general vitamin supplement. How is the injured eye? Do you think he has vision? I would suggest keeping him. Looks like he is already tame and will have a hard time surviving when getting released. Just be careful taking him outside, he might get spooked by something. If he flies away now, he won't survive.
Well, if he has vision in both eyes you can try a soft release when he is a bit older. He needs to spend time in a outside aviary to get used to the area. After releasing he will need a backup food supply. He was very young when you found him (still is) so he never had the chance to follow his parents around to show him where to find food, water and shelter. Without those survival skills, his chances are very slim for longtime survival.