Is It Haram To Be Friends With The Opposite Gender?
Ikram Hawramani gave a very well balanced answer in his article on friendship between men & women. There is nothing in the Quran & Sunnah that explicitly says friendship is haram, however the more close friends they become, the more risky the relationship becomes. They need to maintain a balance. Read the article, it explains this topic very nicely: https://hawramani.com/can-a-muslim-woman-have-male-friends-the-islamic-view-of-having-friends-of-the-opposite-sex/