A heterosexual friend of a homosexual. Adapted from the term "Friends of Dorothy". While a heterosexual cannot (by definition) be a "Friend", they can of course be a confidante to someone who is a "Friend". There is, however, a distinction to be made vs. "friend of a friend", so you have to listen for the capital F.
You're worried about Him? No, he's cool. He's just a Friend of a Friend.