Pet advice

My best mate is in a pickle and needs some advice. She has 2 house cats, she got them just after she moved in to a flat with her fiancé a few years ago. Her fiancé stubbed his toe the other day and shouted in anger, but one of the cats (the male) just flipped and attacked him. He slept at his mums that night because it freaked him out. So he went home the next day and tried to stroke the cat but it just keeps hissing and growling at him. So now the fiancé is saying that the cat has to go and my mate needs to think about what she wants. What could be the problem solver and what would you guys do? Keep the cat or keep the fiancé? The cats were brought up by them too, they're not rescue cats. The cat has been fixed.