It's rude to turn down family members.
Oscar lives in a different town than his family and his brother is calling him to let him know he is in Oscar's town while travelling.
Oscar wants to hear what his brother wants.
Oscar finds out his brother is in town and wants to see Oscar so Oscar says for him to come stop by.
Oscar finds out his brother is in town and wants to see Oscar but Oscar tells him he is busy.
Oscar's brother is happy to see and catch up with his brother.
Oscar's brother is offended that Oscar wouldn't make time for him even though he is in town.