Assalaamu alaikum,
My non muslim brother has a non muslim girlfriend. he is 16. she is alwas around the house. how should i behave to her? is it ok to befriend her or give her gifts? i dont agree with their behaviour and dont want to appear accepting yet at the same time i dont want to be too cold as i dont want to give a bad picture about islam or muslims
Jazak Allah khair

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.

First of all, it is not permissible for a man to have an affectionate relationship with a non-Mahram woman as we clarified in Fatwa 81356.

This ruling applies to a Muslim and a non-Muslim because the non-Muslims are also addressed by the obligations of the Sharee’ah according to the most preponderant opinion of the scholars as we clarified in Fatwa 85569.

Since this is the case, they are both sinful, and one should deny what they do according to his ability. Therefore, you are required to stop your brother and that girl from doing that. If you are able to prevent her from entering your house, then you are obliged to do so, and if not, you should deny this with your tongue while clarifying to them that it is unlawful for them to do so.

Needless to say, a girl [or woman] who is on this situation does not deserve to be gifted or to be befriended. Rather, a non-Muslim should not be a friend of a Muslim, and if, in addition to his/her disbelief, he/she is not chaste, then this applies more to him/her. Indeed, what you do in order to deny them doing what is forbidden by Allaah gives a good picture about Islam, however, you should observe the religious conditions when forbidding evil, as clarified in Fatwa 7583.

Allaah Knows best.