Transmigrated Into the Villain's Family as Their Beloved Darling

I transmigrated into a book as the tragic little brother of the villain, who died young. I thought my four deranged older brothers would tear me to pieces, so I closed my eyes and waited to die. Instead, I heard my eldest brother roar:

“Who changed the temperature of the baby bottle? It should have been here twenty minutes ago!” Third Brother waved the formula tin around and yelled, “It’s been four minutes and three seconds! I’m starving to death!” Fourth Brother clutched a diaper, looking anxious. “Oh no, is the poop about to dry up inside?”