there is technically no top out, they just authorize you for whatever amount based on your income and their interest they imagine you can (barely) afford to pay off. the keys are good payment history on other debt and regular income to support your hefty interest on repayment. i think this is his first time dipping his toe into this mess.
edit: i also imagine that he’s doing this because of his close proximity to legal brothels, he no longer has to wait nor take a horrific bus ride to go to them, so his addiction is in full force and he will get the money some kind of way.