Can you please give me advice? My sister wants to marry a (Muslim) man that belongs to a different culture. Our mother has accepted the idea but my father is still angry about it- he says he's always had trouble with members of this culture in the past, and he will not give his daughter to a man that is not of the same culture as us. My father is a religious man & I feel his reaction isn't Islamic. In this situation, what should my sister do? Isn't my father in the wrong here?
That is a difficult situation. The best solution is probably to be patient. Wait and perhaps with time his heart will soften. If he is a pious man, then it is going to be very difficult for him to harden his heart permanently against the marriage. I know that waiting is extremely difficult for young people eager to marry, but it might be the best course, because efforts to force a change in your father’s opinion may only antagonize him further.
I do not know your exact situation but your father’s concerns about his daughter marrying into a different culture are not necessarily baseless even if they are not fully justified. You can ask people who have married people from different cultures and while you will find many who are happy and fulfilled, there are also many who admit the difficulties, misunderstandings and hardships involved with trying to unite two families of different cultures. Culture is a human creation built over centuries, designed to facilitate communication and interaction between the people that belong to it. When marrying someone from a different culture, the benefits of culture disappear and a lot of extra work is needed to build some basis for understanding between the two cultures. It can be done and some people are willing to do this extra work, while others want to continue enjoying the comfort of uniting with a family that shares the same cultural background.
Personally I am all for intermarriage between different Muslim races and cultures and I find it very inspiring when I hear about successful marriages between different races and cultures, but I respect the right of people not to engage in it if they do not want to.
For more on dealing with parents in Islam, please see the answers on this page: Dealing with parents in Islam