Don't say you didn't help him, for you did. Take solace in knowin' that in the time you had him he was loved and cared for and you did all you could for him. He was able to know love, comfort and consideration at the hand of someone who bonded with him and showed him he was more than just a bird- he was your kid, your friend, your companion and worth everything life had to offer him.
Ya did good, kid.