I've recently been hand rearing some cockatiel chicks to help out a breeder. I've never had a cockatiel and I am in love with them. Our kids have each chosen one to keep. They just want to ride on your shoulder and be cuddled. They are playful and funny, but they do live a long time. 15-20 years is a big commitment. They also need things to chew on and more attention than a smaller bird. A budgie is probably a good starter bird, especially if there's a chance your son will lose interest after awhile. I hope your little future feathered friend brings you a lot of joy!