answer:It sounds unkind at the very least. It could also be rubbing it in the ex’s face. He could well be very angry with his ex. Do you know who broke up with who? Have you considered raising your concerns with your friend? Perhaps your friend doesn’t have any insight on his or her’s actions. At the very least, you can say you don’t like it. In the end, it seems like plenty good reason to drop a facebook friend, to me. But you probably should pay much attention to my advice. I’ve dropped a lot of fb friends (and closed my account), so I don’t have any friends any more.