I kinda feel sorry for Dudley Dursley. He grew up being constantly shown that his parents' affection and love was conditional. Sure, he was already bratty before Harry appeared, but I think a lot of his later brattiness came from fear that things like "2 less presents than last year" were warning signs that their love was fading; after all, Harry never got any presents. Presents = love for Dudley. (Food equals love for Dudley, too; think of all the times Harry was denied food, or given very little of it.) And it can't have helped that he only got more by threatening to throw a tantrum; he had to have been thinking, at some level, that the presents didn't mean as much if they were only given to him to prevent a tantrum. Kids pick up on that kind of thing.
(Also: One of Dudley's biggest worries, at least for a while, must have been "what if being a wizard is contagious? If I catch it, Mummy and Daddy won't love me anymore.")
Then what does he do a lot of to - IMO - try to hold onto their love? He mimics them. Uncle Vernon abuses Harry, so Dudley abuses him even more. Vernon hates Harry, so Dudley gets everyone at school to hate Harry too. Vernon and Petunia both verbally abuse Harry, so Dudley does too. Which also serves to distance him from Harry. Harry is a living sign of what happens to people the Dursleys don't like. Dudley must avoid being like Harry at all costs.
So now imagine what Dudley must have felt like when he had to go on a diet. His parents kept talking before about keeping him fat because Vernon was fat. But going on a diet means slimming down, being less like his father. Which must have felt terrifying to Dudley. "What if I get skinny like Harry and they hate me?" Which adds incentive to cheat on his diet. It also makes him become very grateful when he finds boxing makes his parents proud of him, it balances out his weight loss in his mind, especially since most of his fat turned into muscle. But in the back of his mind, he's still worried, so he acts out his worry and frustration by becoming an even bigger bully, doing what he saw his parents doing all his life: hurting small children. Which may have been partially another means of mimicking his parents.
For all Harry went through in the years after being accepted to Hogwarts, Dudley had it worse in some ways, because his struggle to maintain his parents' love for him never went away, never got better, at least not for a long time. In fact, the distance from going to his own boarding school and the fact Harry wasn't there at they Dursley's house except in the summertime had to make him feel worse, probably worried they'd forget about him, or worried that they'd miss having a slave/punching bag, and turn their negative attentions on him to make up for the lack of Harry.
And his terror from Hagrid giving him a tail had to be pretty scarring, too; his parents hate anything weird or unusual, he had to have been petrified that they would hate him for having a tail. And even though he dodged that bullet once, he was terrified of adult wizards ever since, worried he wouldn't be so lucky in the future.
Oh yeah, and his snitching on Harry, getting Harry into trouble, was likely a way to turn negative attention back to Harry. Like, "I know you love to abuse Harry, so if I help you by giving you more reasons to do so, that means you'll appreciate it and love me more. Right?"
This all is probably the source of Dumbledore's comment in the sixth book about the damage inflicted on Dudley.
And then, after everything the Dursleys put Harry through, even though Harry was angry with him just before, when Dudley realized that Harry had saved his life, he got his first ever taste of unconditional love. Harry might not have liked Dudley, but they were still family, and so he saved Dudley. Never mind that Harry would probably have saved him even if they weren't family, as long as Dudley wasn't a death eater; Dudley doesn't know about Harry's "saving people thing." What's more, from what he's observed of his parents' behavior, Dudley might think or worry that as much as his parents claim to love him, in the same situation they probably would have fled for their lives and left him behind.
Of course, Harry then saves all their lives again by getting them into hiding from Voldemort, which reinforces Harry's goodness. (A concept which, incidentally, probably made Dudley start to realize how horrible his parents were, since they were obviously wrong about Harry and thus hated him for ridiculous reasons.)
And also, a lot of the same kinds of things must have gone through Draco's mind in regards to Dobby.
Anyway, given all this, I think Dudley having a magical child would be good for him. I think he would learn from his parents' mistakes, and his own upbringing, and be good to his magical child.
This was cross-posted from
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