The prodigal son's older brother complained his father had never given him what?

Answer: A young goat

He said, "You never gave me even a young goat (KJV: a kid) so I could celebrate with my friends."

“But he answered his father, ‘Look, all these years I have served you and never disobeyed a commandment of yours. Yet you never gave me even a young goat so I could celebrate with my friends.”— Luke 15:29 (BSB)