There are a number of lessons to be learned from this experience. The first is that for many the Spirit is still able to touch us with the call to repentance, and we are capable of responding. We have the ability to turn from the things which had separated us form the Spirit, and return to a closer walk with the Lord. These things it appears that Nephi's brothers did (verse 5).
Because we know the future history of Laman and Lemuel we also know that a period of true repentance is no guarantee of future humility before the Lord. Our ability to enjoy the fruit of the tree of life depends upon our enduring to the end, and not trusting that a single bite of the fruit will suffice. Remember that in the dream there were many who tasted and yet fell away. While in Lehi's dream Laman and Lemuel do not even approach the tree, it is clear that this was the license of vision, for they did have some periods when they were able to be humble and enjoy the blessings of the Spirit.
The next lesson is the great joy that those who love us feel when we return to the proper path. Joy is truly great for those who accept the returning prodigal sons.
The last lesson is perhaps the saddest. Nephi preached with power to his brothers, and they felt it. They humbled themselves before the Lord, to the point that Nephi proclaims: "that I had joy and great hopes of them, that they would walk in the paths of righteousness" (verse 5). For all of the power of the prophetic vision Nephi had so recently experienced, for all of his obvious connection to the Spirit, for all of his righteous hopes and desires, he nevertheless did not know the future of his brothers, and at this point was able to take joy in their temporary conversion, at the time unaware of their eventual separation, not only from the rest of the family, but from the Lord.