All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
Indeed Islamic law has legislated to deal kindly with the non-Muslims who do not harm the Muslims. Allaah says (which means): {Allaah does not forbid you to deal justly and kindly with those who fought not against you on account of religion and did not drive you out of your homes. Verily, Allaah loves those who deal with equity.}[60:8]. Therefore, it is permissible for a Muslim to break the fast with non-Muslims and accept their invitation especially if they are relatives or those whose hearts one hopes to soften towards Islam. However, a Muslim has to be sure that the food that is presented to him is lawful; no pork or the like, or meat that is slaughtered by those of whom we are not allowed to eat (people other than the people of the book).
Allaah knows best.