Cyberbullying?

I need some help from you now ☺🤝🏻🙁 I'm currently homeschooling and my brother is also sharing a laptop. I always have my video conferences in the morning and my brother in the afternoon, yesterday I brought him the laptop that he had in his viedekonferenz, the next day I took the laptop out of his room, I was still logged in to his account, I wanted to log out as normal, there was still a chat open from him and a younger girl when I was just before me I saw that there was a swear word in the chat, so I also looked at the whole thing, it looked like he was having an argument with this girl, because he wrote to her: "You f * ck, can you not do anything else?"! " At first I was shocked because my brother is not really a person who would offend someone in this way, but I was wrong, I still logged out and logged on to my account, after my video conference I talked to my brother about it and He then said to me that I shouldn't tell my parents anything, I want to tell my parents but I'm afraid of what my brother would do with me then, although he knows very well that the teachers can read the chat and in general can see who is writing with whom, does anyone have any tips? 🤍

I would stay out of it, because if the teachers have insight, everything is sorted out. They'll tell your brother if he doesn't behave appropriately

Mhh if the teachers know that he wrote that and who should they then be aware of it?

But I think that if nothing happens then you could talk to your brother about it again and ask him why he writes things like that and that you don't write something like that, especially not to a girl, it sounds like you are fine get along with him.