Final answer:
Santiago's father reacts supportively when his son expresses his desire to travel. This relates to the obstacle of societal expectations and obligations.
Step-by-step explanation:
Santiago's father reacts to his son's desire to travel with understanding and support. He suggests Santiago take a trip North, showing his affection and respect for his son's aspirations. This reaction relates to one of Coelho's obstacles, which is societal expectations and obligations. Santiago's father represents the obstacle of societal pressure to conform and stay in one place, while Santiago desires to explore and follow his own dreams.