My brother traumatized me and nobody takes it seriously

I have an older brother who i’ve never been crazy close to but we live together and know each other well enough.
I’m known to be an animal lovers and very sensitive, and a few years ago he had the bright idea to send me a video of a cat being killed by peoples (TW), the cat was being put in a big mortar and crushed with the tools that goes with it, you could see it try to run away but been captured and put again until you no longer can tell what it was. At the time i was around 10, a bit older, and it shook me up, i cried, even threw up i couldn’t get the images out of my mind and could no longer see a mortar without feeling off.
I’m now 16 and still have to deal with this especially with everything you get exposed to on the internet that reminds me over and over again of that.

I really wanna find a solution to this cause it’s been really hard to live with it, sometimes sobbing just thinking about it since it’s now linked to everything else relating to animal cruelty.

Thanks for reading this and i’m sorry if it sounds off, english is not my first language.