Its very painful to be separated from your roots and giving away your identity. Your father did what seemed right at that moment. I will say he is a very brave man. Its not easy to let go off a part of you.
Btw have you read Zoroastrian history, we almost went through the same situations but it was centuries ago. In the Persian conquest Zoroastrians were forced to leave Iran to save their religion. We were well accepted by the Indian culture but there was a lot of give away in the bargain