Seems to me that older siblings can be a lot of help with homework, getting young kids into pajamas or bathed, chauffeuring the younger ones around, making sure kids doing chores or depending on age help with discipline. Basically they are unpaid babysitters for parents to use to help with younger kids at no charge. Maybe we should go unionize haha.

All of those would depend on the age of the older child as well as the age of the younger children and the responsibleness of the older child along with details on the different tasks.

Discipline could mean a simple time out or being placed in the corner or it could mean a spanking. Helping get ready for bed could be simply telling the child to get ready for bed or come and help in the bath. Chauffeuring would depend upon the license status. Helping with homework is probably the only definite for sure answer to that question without knowing all the other factors, but you could have a very unintelligent or dumb older sibling who wouldn't be much use for that.