At home, the poor kid had to go to a full day of private Chinese school every Sunday to learn language and culture. He was obviously fluent in German and Chinese but he spoke English with a Chinese accent, not German. When he did funny/strange/crazy things we didn't know to whether to blame it on the Chinese or German.
I think he got teased/bullied a lot in Germany. He was definitely an awkward kid but here everyone just assumed he was American.