Praise be to Allah.
My advice to these people is that they should learn medicine, because in our country we have a great need for it. With regard to mixing, in our country – praise be to Allaah –a person may be able to avoid that as much as possible.
With regard to traveling to the kaafir countries, I do not think that it is permissible to do so unless certain conditions are met:
1 – The person should have sufficient knowledge to ward off doubts, because in the kaafir lands there are those who try to instill doubts in the Muslims so as to take them away from their religion.
2 – That the person should have sufficient religious commitment to resist desires, so one whose religious commitment is weak should not go there, lest his desires overwhelm him and lead him to his doom.
3 – There should be a need for his traveling, such as this specialty not being available in a Muslim country.
If these three conditions are met, then he may travel; if one of them is not met, then he should not travel, because taking care of his religious commitment is more important than taking care of anything else. (See more details on this issue in Majmoo’ al-Fataawa by Shaykh Ibn ‘Uthaymeen, 3/28).