Responses
Actually you don't.
Unlike the way others have stated them what you said actually explains why things seem a little off. I mean from his perspective it does seem unrealistic to accept new people into his life the way he has and after what he's experienced. I'm not saying that he should necessarily be suspicious of people but more that he would want to keep other people from being hurt just as his family has been.
Plus him being slightly aloof and cold would up the angst meter in a non-cliched manner.

The romance plot is kinda iffy but it was nice to see him behaving like a normal kid