Should she cut off her ties with her adopted brother who has left Islam (is an apostate)?

My friends brother is adopted. He was not breastfed by her mother. Her mother got him when he was 3 months old from an adoption agency. There are no blood ties between them. She is muslim, he is muslim but he reverts back to the kuffar way of life. If he backbites her and he tells lies about her to other people, Can she cut ties off with him since he is adopted and there is no blood between them from the mother or father or anybody else? DOEs she still offer him salaams even though he is a revert

Praise be to Allaah.

This person has no ties to this family, whether through blood or through breastfeeding (radaa’ah). On this basis, if he is a mature and responsible adult, it is not permissible for him to mix with them and look at that which is forbidden. This is the case if he is still Muslim, let alone if he has left Islam.

So it is not permissible for her to shake hands with him, or to be alone with him, or to uncover in front of him, because he is not a mahram. (See also question # 5538). She should not greet him with salaam nor return his greeting so long as he is a murtadd (apostate). We ask Allaah to keep us all safe and sound.