Is it considered emotional or mental abuse?

It is definitely not coming from my relationship at all. Our relationship is solid. But it came from one of my good friends’ relationship and how he told me a few things about what’s going on between them. Of course, it’s not my place to get involved in it. He only simply vents it to my fiancé and I which is totally understandable. Anyways, there’s a few things he mentioned kind of bothered me a bit, maybe a bit too much. For example, he mentioned his girlfriend told him how bad she wants to punch him that one of teeth would come out. When I heard that, it raised an alarm ring in my head. He even said he thinks it’s hilarious how she threatened him and he found her anger super sexy. Whatever. But is this kind of talk with threats considered a mental or emotional abuse?

Edited: it was during an argument. None of teasing banters or anything like that.