As I understand it there is an obligation (See Shulchan Aruch Yoreh Deah 240:22) to honor an older brother similar to that of honoring one's father. Since the obligation to honor one's father can have strong implications, in what way (if any) is the obligation to honor one's brother different?
The Gemarah (Kesubos, 103a) brings a statement that the extra vav in the word "v'es" in "Kabeid es Avicha v'es Imecha" is there to include your older brother for the mitzvah of Kibbud Av. Whether it means the eldest brother or any older brother is a discussion amongst Rishonim.
The simple implication of such a statement is that whatever would apply regarding honoring one's father would apply to honoring one's older brother. The difference being if it is a choice between honoring one's father or brother, his father's honor is primary.
But if one looks in the poskim one will see that some hold this obligation is not the same level as the obligation to honor one's parents.
There are also poskim who state clearly that it does not apply to an older sister.