The Superflex curriculum is a good one for kids this age. My son loves it and I use it with some of my students who have social difficulties. The creator, Michelle Garcia Winner (socialthinking.com) has a wealth of knowledge and resources.
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You could also try "social stories" or scripts that help him understand the nuances of social interactions that he may not pick up on innately yet. Things like, how to act when going to a playground, why it's not okay to hurt other people, how to act when you have hurt someone... (just taking from your immediate example). You can also make stories about transitions that are helpful with many kids. I put a collection of stories in a binder for ds, including pictures of him, and he loves it.Â
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These programs were both developed for children with autism; however, they are useful and fun for anyone with these kinds of difficulties.