I am guessing he will be all right, but keep him quiet and dont let him get cold. I heard from an avian rescue that birds have a remarkable ability to recover from head injuries if kept warm. I dont know how true this is. One day while walking into work (hospital) I saw a beautiful yellow cactus wren hit the glass windows at about 4 stories up. It fell to the grass. I ran outside and picked it up. It was stunned and not moving. I cupped it in my hand and took it into work. I put it in a shoe box and called the rescue. While talking to them, they asked me something and I opened the lid of the box to check. Out he flew! He flew all around the dept. and headed into the OR's! Everyone was scrambling to keep him out of the ORs. We corraled him in an office and I took him outside and let him go. The vet rescue said that me holding him warm in my hands may have saved his life.
I hope your little bird recovers just as well.