theres 2 years between each of my 3 youngest siblings and i remember my little sister absolutely adored my little brother, she used to call him dolly. I was very close to my brother who is 3years younger than me, we were best friends.
i know its not the same but when my nephew was born nicole hated it, she felt so pushed out by the family and went from being an independant child to being very clingy. She hated me leaving her. She loved her cousin tho.