Although unnamed, these brothers certainly included Laman and Lemuel. Whether Sam was involved is unknown. When Nephi asked the cause of their disagreement, they admit to being puzzled about Lehi’s reference to the olive tree’s natural branches (1 Ne. 10:12–14). From the book of Jacob, modern readers know that it is a long allegory by Zenos (Jacob 5:1) contained on the brass plates. Because Lehi had read at least some of the plates (probably all), the allegory of the olive tree would be clear to him. Just as clearly, neither Laman nor Lemuel had read this section or they would not be confused about how it related to Lehi’s dream. Both in lack of general understanding and lack of preparation, Laman and Lemuel were unable to answer this question.
It is interesting that when Nephi heard his father’s words he was most interested in the entire experience and received a vision to understand not only the tree of life symbols but the vision of the future to which his father referred. Laman and Lemuel do not ask about the tree of life or the Messiah. They ask about the branches of the olive tree. Perhaps they understood that this part of the prophecy was about a reuniting of the scattered with Israel and they wanted to understand when. No doubt they saw it as a prophecy that they would be able to return home.