Showing equal love and attention to one's children

I want to know that if a child was expected to do certain things (provide,work etc) for the family by a certain age even when having other responsibilities isn't it only fair to expect all the other children, when they reach that age to be expected to do the same (especially since they have lesser responsibility than the first child did) as in Islam all the children should be treated equally, so just like they will have give driving lessons to the others as they did for the first child the same way the other children should be expected to do the same chores and work for the family the way the first child did.