My Cat is acting weird. Advice?

[TheAnimeQueen]

I have two cats, a Male and Female cat. (They are brother and sister). A couple days ago we figured out that the male cat has a Urinary track infection. He got taken to the vet and now he is home but he has to keep a iv bag on his penis so he can urinate. The female cat is acting mad at him and she is also acting mad at me too. I thought she was just mad at the Male cat because he smelled like the vet and not like her brother but it’s been a day and she is still mad at us humans too. Does anyone have an idea why she is so mad at everything?