No the cat died so he hid it from his brother so he wouldn't feel sad or cry.
Ch.6 pg.14-16
His hands were covered with blood. I think Yukito killed the cat.
If the cat was really that sick in can cough up blood before it dies. That's what happened to a cat I knew when I was 10 it coughed up blood and we went to take it to the vet and they died before we got there . I think there's a 50/50.
I think we're leaving out the "hit by a car" option. Yukito may have gone to find the cat and found it dead near the road. He probably buried it quickly so Kuruto wouldn't see it, hence the blood on his hands.
so and what happend with the cat? did yukito really kill it? somehow i'm really confused..