Complex sentence: There, he is furious upon discovering that the vault only holds the Rich family's most precious memories and keepsake treasures--nothing that is valuable monetarily; he then learns that the Rich family keeps their money in banks, the stock market, and real estate.
Split into simpler sentences: There, he is furious upon discovering that the vault only holds the Rich family's most precious memories and keepsake treasures--nothing that is valuable monetarily. He learns that the Rich family keeps their money in banks, the stock market, and real estate.