It is of course, it is possible he been abused. But also is possible he is changing in his charater, and personality, as he get older, and come into his new age and new life in school and such. I think it is very much nature, that as we grow up, we will change some. Some things we have interest in before, perhaps we do not now, and perhaps even to become more thoughtful and less social then before, with not having nothing bad to cause such change.
I just think it is perhaps possible that sometime we will 'see' abuse in people because of what have happened to us. Not everyone behave ways they do because they was abused. Some do. Some do not.
I hope that he will be all right, and he not been damaged.