Quote Originally Posted by Argranade
I would not put him to sleep,

Why not just keep him in a huge cage with many toys, treats ect.. and just let him live his life with out human touch, maybe he just enjoys looking at people talk to him instead of trying to touch him or work with him. I'm sure if he was given a home with out any other birds and he was just talked too every single day gently and given treats he would at least not mind that.
Well, i have read that Cockatoos enjoy human touch, and without it they are very unhappy.