As stated previously, Boone had his own familial issues with Shannon. Boone tried to be helpful from the beginning of the post-crash CPR, which Jack told him he was doing it wrong. Boone tried to fit in to a fractured beach camp, but he never found any true connection.
It is probably because he was a loner, like Locke. Maybe Boone needed an older brother figure to cope with the stress of being a castway, estranged from his stepsister.
Originally, Boone was supposed to be a major presence in the LOST story. However, he got shifted to a secondary role after the emergence of Jack as the lead male character.
Still, Boone was involved in two key moments in the series (or so we thought at the time of original airing): finding the Hatch and finding the small drug airplane.
The Hatch was supposed to give us viewers the Big Answers to the current island mysteries. It would have been a window into what was the island, who were the Others, and why strange things were happening to the castaways. At the very least, it would have given the beach camp real shelter from the smoke monster, wild animals and the Others attacks (but strangely, that never happened).
The plane was supposed to help guide the viewer into the soul of the island, because it was physically impossible that an African small plane could have crash landed on a remote Pacific Island. The presence of the plane was either a) an illusion taken from Eko's memory; b) an echo of a parallel dimension or realm; or c) a magical trope to create faux drama.
Boone took it upon himself to go up on the cliff to investigate the plane for clues and a possible chance to be a hero, to find a radio and call for help. But the plane fell, and Boone was severely injured.
It was Boone's traumatic demise that got Jack to "let go" of a patient, for there would be no "medical miracle" on an island that allowed at least two big miracles: Locke being able to walk and Rose's cure for cancer. By Jack being unable to save Boone, some consider his death "saving" Jack from the haunting criticism of his late father.
Locke would justify the reckless behavior of his subordinate as "being the sacrifice that the island demanded." But we never get the sense that the island was a conscious being that needed human blood in order to survive. (This is a very ancient, pagan-primitive ritual belief system). Why Locke made that assertion could only be to ease his own guilt for allowing Boone to do a dangerous task.
It foreshadows Locke's only senseless demise when he tried to be the hero (getting everyone back to the island). Perhaps self grandeur is why both Locke and Boone are alone in the sideways church. For some reason, they could never connect or find their own soulmates.
