Really what creates people like Tybalt has nothing to do with how much discipline or punishment he got as a child. They could’ve beat him on a daily basis—or even beat and abuse them, as it’s rumored Donald Trump did to Don Trump Jr.—and he’d still turn into the same little shit he has. He’s a little shit because they pay his bills. That one fact undoes any discipline they ever gave him.
Contrast Tybalt with Sage, who not only won’t take the Burkes’ money, but yells at Quinn for even suggesting the idea at their car wash. That’s a line she refuses to cross. Crossing it for Maya was a big deal to her. Yeah, it’s because she’s emotionally fucked up in different ways. But enough about her; back to Tybalt.
Bitch doesn’t have a job. The Burkes probably got him the preps presidency too. He buys himself ridiculously expensive watches, tailored suits, a cello, imported sparkling wine (which he wastes for Rooster likes), and hired an entire sorority as escorts for his frat’s party. He can buy all the friends he wants, and never has to develop kindness, empathy, loyalty, a sense of humor, a talent, or any of the other qualities which usually get people to like you. The money easily compensates for his shit personality.
He thinks of the Burkes’ wealth as his wealth—and y’know, if they never turn off the money tap, he’s not wrong. In order to justify his life and behavior to himself, he’s obviously adopted a social Darwinist worldview: somehow he’s worthy of it. All evidence to the contrary, somehow he got himself there. As he tells the MC in the showers (in my game he’s called Trey, and here he’s knocked Tybalt’s bridge out):
The rich people I know, are fully aware this is exactly what their kids will turn into if they spoil them. Doesn’t matter how much they correct them. Money is power, and power corrupts. So they simply don’t give their children money. Their kids don’t get allowances; they’re required to work for it. (Sometimes with household chores; sometimes with actual jobs.) They’re fully aware turning their kids into entitled brats like Tybalt will ruin them for life, and they’re not having that on their watch.
Now, if they die and the kids inherit their wealth, and that corrupts them… well at least they tried.