Helaman¹ was one of the three sons of King Benjamin, alongside Mosiah and Helorum (Mosiah 1:2). Benjamin had his sons taught in the language of his fathers so they might become men of understanding and know the prophecies spoken by their fathers (Mosiah 1:2).
Benjamin also taught his sons concerning the records engraven on the plates of brass and the plates of Nephi, telling them that without these records the people would have suffered in ignorance, not knowing the mysteries of God, and would have dwindled in unbelief like the Lamanites. He charged them to search the records diligently and keep the commandments of God (Mosiah 1:3-7).
Helaman¹ is named only in this passage; the record gives no further account of him. When Benjamin conferred the kingdom, it was Mosiah, not Helaman, who received the throne and charge over the records (Mosiah 1:10, 1:15-16).