The main role of the sentence "About my brother, suffice it to say that music to him was everything-love and friendship, ambition and life." in the passage is:
3. It reveals why Daniel stayed on the island with his violin.
In this sentence, the narrator is emphasizing the deep connection Daniel had with music, portraying it as an integral part of his life. This connection to music explains why Daniel chose to stay on the island with his violin instead of leaving or seeking help. The sentence highlights the significance of music to Daniel, which ultimately influences his decision to remain on the island. It showcases how music was a crucial factor in Daniel's life and decision-making process during his time on the island.
