Complex sentence: Teddy reveals that the only witness was his brother Barney (Gyton Grantley), who had been sitting on the town silo at the time and saw the whole thing, but due to being developmentally disabled, no-one thought to ask him.
Split into simpler sentences: Teddy reveals that the only witness had been his brother Barney (Gyton Grantley), who had been sitting on the town silo at the time and had seen the whole thing as it had happened. But due to his being developmentally disabled, no-one had thought to ask him.