Your friends have helped you a great deal in drawing the character sketch catering to the mentioned chapter. Hope this helps as well:
1. Harold has been shown to be a very intellectual student, who has been brought up in a very protective environment. He was considered to be a prodigy who was born into the family of the Brambles. He was completely different from other kids, devoted to his books very religiously. He was very admirable as he was an example of 'perfection'. He was a 'model of goodness and intelligence'. He started feeling superior, growing in stature in his own life. He was a good singer. He got engaged in more important issues in life and became extremely selfish and self-centred.
2. Mr. Bramble, was a professional heavy weight boxer. He was a tough sports person, yet a sensitive father who cared most about his son’s education. He like his wife was afraid that the truth about his profession might affect Harold’s education adversely. Thus, Brambles kept the truth from Harold. Though Mr. Bramble was a proud boxer, he was ready to forsake his profession for his son. However, the irony was that on knowing the truth, Harold was happy that it was his father who was Young Porky.
3. Major Percy Stokes, brother of Mrs. Bramble, is not a major character in the story, however, has a distinguished role to play. He is as much concerned about Harold and his academics as Mrs. and Mr. Bramble. He made sure that the father's profession's truth is well kept from the boy. It was Percy who made Bill change his mind to not fight at the Nationals through his letters, until Jerry Fisher disclosed it all to Herald. It was only on being asked by Harold himself Mr. Bramble decided again to fight.