I am at a total loss. My brother is 22 years old but has the mental capacity of about 8. He has seizure disorder, autism, and a litany of other health problems due to brain damage at birth.

He was playing something on his N64 I set up for him and I was downstairs playing on my phone. I was house-sitting (technically babysitting) for my parents. (Yes they are in the process of getting him in assisted living/home for adults with issues like this).

Suddenly out of nowhere I hear a hideous scream, inhuman even. I race upstairs and my brother has the door shut and barred. Horrified, I pound on it and ask what happened and he keeps saying nothing over and over. I demand he open the door and he said no he’s busy. He won’t tell me what I heard was, or what happened. Freaked out, I race downstairs to the garage and grab my dad’s stepladder and climb up to his window, and holy fuck. My brother is hunched over chewing on his fucking now-dead guinea pig. There’s blood ***everywhere***.

I immediately called 911, my parents, and his social worker and I don’t know how to handle this. He’s currently under observation at a mental hospital, my parents are pissed I “let him” do that, and that I called 911 over that, and I am not sure how to cope with this mentally. I mean, what the hell.