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In a video game I'm playing, the main character, who is a middle-aged man, and his child-like young friend meet a farmer, who seems to address the younger of the two as 「ボクちゃん」.
オレは ピーター。この はたけの オーナーだ。オヤジと ボクちゃんは どうして ここに?
What exactly does ボクちゃん mean here? What does his choice of words tell us about his opinion of the other two men?