drama. I need advice

So my friend is going through a bad break up. And he keeps telling her loves her but he wants to see other people and all she's been doing is crying. So I texted him to tell him to stop confusing her because that's not okay. And the thing he decides to bring up is "I wonder if your bf knows you gave him a vaginal infection on purpose" I said ok dumb ass a "yeast" infection is what all women experience 1+ times in their life time. And he said "well at least im not the one spreading STDS" I said that it wasn't an STD and he continued to say whatever everyone knows... He's not popular at all, hated by me and all my friends. But the thing is, I sent my friend those screenshots of her bf and I and she said he had staph infection and she also said sorry im not on your side I still love him. Im like...what the fuck??? I don't know what to do... Can someone give me some advice? Im not sure what to do here