Im not a parent so perhaps my advice is not any good, but I thought I would offer a suggestion. Perhaps you could start taking him to visit people or volunteer with people who have much less than you, start to get him to realise that he is bloody lucky to have the life he does. Even volunteering with the disabled can be a big wake up call, teach him to be appreciative that he has a functioning body and a loving caring family. Being only 11, children can be extremely selfish but kudos to you for trying to redirect this behaviour. You sound like a really great parent.