Salam aga, how are you? My brother is in Australia and also follower of Ayatollah Sayed Sistani dz. he was staying with our brothers in faith. but now they will be joined by their respective families. so as he is alone he has to move out the house. now the ppl with whom he will be living are non Muslims. and all are students of hotel management so they know to cook and to save cost they will be cooking turn by turn. SO IS IT PERMISSIBLE TO HAVE FOOD COOKED BY THEM. And also he will move out if he finds new students who are brothers in faith.

wsalam, if non-Muslim but Cristian or jews then only take care of halal and if they are Hindu or Buddhist then he can't eat better to find other place
Allah Subhnatala give him strength