Not really. Kamui was always considered the weird fatherless kid, especially once his powers awoke and odd shit would sometimes happen when he got irritated. However, I always imagined he had some quiet admirers among the other kids that weren't really popular, because when the kids that were aggressive about ostracizing people decided to harass him, he made it so they weren't usually up for harassing anyone else for a while.
In my headcanon he almost found a friend in an American girl that was living on one of the local US bases with her father, but she moved away before the friendship went anywhere beyond 'friendly acquaintance'.
Did Fuuma have any thoughts/assumptions about why Kamui had apparently turned into a complete douchebag when he came back to Tokyo?