Many practicing Muslims living in non-Muslims countries migrated here for economic benefits and not for the purpose of Da'wah or any other permissible purpose. Then Allah guided them and they started following Deen. One of my friends is among such Muslims. I was discussing this issue with him and he seemed uncomfortable about leaving USA and to settle in a Muslim country. He said his family will not agree to leave USA. He intends to study Deen in a Islamic school in USA and then get involved in Da'wah so that his staying in USA is justified. What is your point of view about such cases? My second question is that suppose a person in his childhood settled in a non-Muslim country so if he wants to migrate to a Muslim country then should his mother-land (that he belonged to) be preferred?

Praise be to Allah, the Lord of the World; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

No doubt, living in a non-Muslim country even if there is religious freedom, causes many unavoidable harms. Naturally, the one who lives with non-Muslims, mixes with them and thus he will be influenced by them in his faith and belief. It is very possible to be highly impressed by their advancement in many sectors that has not the weight of the wing of a mosquito in Allah's Sight, and begins to love them and admire them. It is also very possible that his hatred may be reduced or completely eradicated for their Kufr, evils, dissoluteness, etc. Since an individual spontaneously becomes familiar with what he sees and lives with; no doubt thus staying there is very dangerous. Also the children in these countries are subject to enormous evils and the laws of these countries do not permit parents to control their children as they should.
However, there is no harm for the one who lives there and wants to study in Islamic school to work in the field of Da'wah' upon completing his studies.
Once again we remind you that living permanently in such countries is not permitted.
As for the one who wants to migrate from such countries to the Muslim countries, it does not make any difference whether he migrates to the country of his origin or any other Muslim country. All the Muslim countries are actually the place of all Muslims, so one may live everywhere in a Muslim territory.
Allah knows best.