Loneliness can lead to emotional problems throughout a child's life. A big brother showing a little brother how to play baseball or how to build a treehouse is an example why a brother is important. A big sister showing a little sister how to cook or fix supper can show the need for a sister. Not having brothers and sisters can lead to a lonely life. Influence from a brother or sister can be important as a child.
Many children do things without knowing whether they did right or wrong.
An older brother can be there to show little things like how to treat guests or the difference in respect or rudeness. Older brothers and sisters play a major part in how the younger child grows up. Many times a younger brother or sister will act as the older brother or sister did. Having an older sister can mean the difference between knowing proper manners or not, because older sisters seem to teach the younger ones how to act at the table or how to act while company is present. A big brother who is a big standout at school can play a large role in how a younger brother strives to do as he is growing up.