How to be a good brother/sister.
If you want to be a good brother or a good sister you would need to be a very good role model so when they become older they would become helpful and kind.
If your little brother feeling scared of afraid you should help them face their fears and become not scared. Like if they a so afraid of a new pet like a dog you should pat the dog.
Because when they see you petting the dog they would not feel much afraid and they might pat the dog and love the dog.