I am not sure what Moroni did to "[prepare] the minds of the people to be faithful unto the Lord their God"
(Alma 47:7) As I consider it, I think of this quote from Joseph Smith,
Nothing is so much calculated to lead people to forsake sin as to take them by the hand, and watch over them with tenderness. When persons manifest the least kindness and love to me, O what power it has over my mind, while the opposite course has a tendency to harrow up all the harsh feelings and depress the human mind. (Joseph Smith, Nauvoo Relief Society Minute Book, p. 59, History of the Church, 5:23–24.)Moroni said, "Charity never faileth". So we must all pray with all the energy of our hearts that we may be filled with this love. Pray for your son. Serve him. Ask the Lord, in what ways you might be able to touch his heart, or that others might be placed in his path so his heart might be touched. I like this modern casting of Charity never faileth, "Love Wins!"
I know the deepest and longest lasting effects in my life have come from when those close to me loved me, forgave me and served me.
And trust in the Lord. There is no need to despair when we have faith in the Lord's timeline. To me that may be one of the keys of "charity never faileth". The Lord is patient with us. He will reach out as often as we reach out to him. Your son will be blessed by your faithfulness, if you will pour out your soul to God for him.