Well, we have to remember that his whole world was turned upside-down when he was like 9, just a kid. As Nadine said, he just needs love. Imagine being ripped away from the person you love most in the world, and then she comes back (kinda) but then you find out that she IS there, of course you would do the same thing. Of course he cried, Wanda just kinda reminded him how his entire family was taken away from him, and then she refused to answer if his sister was still left inside, or dead. And the hugging part: he just got his sister back, who he thought was gone forever. Of course he's messed up, that's a lot to take in for a kid, he just needs some time to realize that this time nobody will be taken away from him, because they're safe again.