Stan (Charlie's accountant) tells Alan that he thought Alan was the smart one. But as Stan is leaving, he tells Alan "nice to meet you, sport", meaning he had just met Alan. So, how could Stan think Alan was the smart one, when he had just met him.
Most likely, Charlie talked about his brother, the chiropractor. A chiropractor had a lot of schooling - more than a musician and Stan would have thought that Alan, the chiropractor, was the smart one compared to Charlie.
Most likely, Charlie talked about his brother, the chiropractor. A chiropractor had a lot of schooling - more than a musician and Stan would have thought that Alan, the chiropractor, was the smart one compared to Charlie.