Final answer:
The brother's recognized loss on the sale of the property is $14,000.
Step-by-step explanation:
The brother's recognized gain or loss on the sale of the property is a recognized loss of $14,000.
When Luke sells the property to his son for $24,000, he incurs a loss of $14,000 ($38,000 - $24,000). Since the son sells the property to his brother for the same price of $24,000, the brother's adjusted basis will still be $24,000. Therefore, when the brother sells the property to Monica for $42,000, he incurs a loss of $18,000 ($24,000 - $42,000).