He speaks to the boy and encourages him to respect his sheep, which encourages the boy to remain a shepherd.
Explanation:
The crystal merchant influence the boy's actions by sharing his story and his regrets, and the crystal merchant teaches the boy that some people would rather fantasize about their dreams than live them.
He gave Santiago money to buy a flock of sheep because he shared his son's dream of traveling the world and the stones he gave Santiago help the boy to recognize omens, which will help him on his journey to find his Personal Legend.
