Can you change the fate of a child as a teacher?

I remember when he first arrived to our school. He was eleven. He has been to UK for a year. He was very bright and learned the vocabulary quickly. He was one of the most successful students in the induction group. Always asked questions and listened to the answers very carefully. During parents' evening, his dad enquired about his levels and he seemed pleased with the teachers' comments about his son.
I had high expectations of him and motivated him to study higher education. After achieving a certain level of English, we stopped supporting him intensively because I knew that all he needed was in-class support and monitoring.
In the past year, his behaviour has changed. He became oblivious to his lessons and actions. He parted from our support towards an unknown place.Bad company did not help him to keep up with good standards. He was going through teenage problems alongside with a family who did not spend quality time with him. His sister told me that recently, he was going out and coming back at midnight. This caused a lot of problems between his father and him. The school was in regular contact with the family. It seemed like nothing we did worked for him. Or was it the case?..What else could you do for students like him as a teacher? I admire some teachers who start working with a student and change the destiny for that student. However, when you have over 30 students in one class and nearly 60% of them with similar problems, I suppose as a school, more structured mentoring is needed.
Due to his bad behaviour, his dad saw the only way out is to send him back to his own country. He was not told that he was going there for good. He thought that he was going there for holiday. When he arrived there, his father told him on the phone that he was there to live for the rest of his life.
There are many problems in his country such as; poverty and civil war.
http://en.wikipedia.org/wiki/Democratic_Republic_of_the_Congo  
  
Was that the only solution? I am not sure...However, when his father took the decision, he did not see that it was necessary to consult the school or anybody else. This is the point where your role as a teacher ends! This is the time, you stop talking! This is the time that you understand, as a teacher your power is limited and your hands are tied!