There are siblings who LOVE to live in their sibling's shadow. The adulated sibling/siblings have something that these other siblings lack whether education, looks, money, relationships, friends, or success. They WANT what the adulated sibling/siblings have but refuse to exert any effort to obtain what they wish/desire. They latch on to the more successful siblings in one way or another.
There are less successful siblings who maintain that it is THE OBLIGATION of the more successful siblings to supply them with the lifestyle they desire. They feel that they SHOULDN'T have to make any effort to obtain friends, success, & relationships on their own. They intend to LEECH off the more successful siblings. They feel that their siblings are THEM & they ARE THEIR SIBLINGS. The sibling relationship is a complexity beyond words. The sibling relationship is one of the most puzzling relationships, even more puzzling that of parent & child.