@F there was an author's note that explained it. TH didnt raise him, he's ageless and a dragon and only took on the form of a kid because that was the first person he saw in the human world so he mimicked his appearance. He becomes an adult physically very quickly as he adjust better to the world o humans. Nothing happens between them for a very, very long time. He's never had the mind of a child but he was just ignorant and innocent and since the day he took on the appearance of a kid, he's only been abused. I'll see if I can find the link, but the author's intentions wasn't to cast them as father & son at all