well ignore him... tell your parents that your little brother is forcing you too give robux to him for no reason... and thats all i have to say... cuz my younger sibling never treats me like that... i dont have any experience... sry
oh wait, I wrote that wrong, I meant 'It's not like he's actually forcing me", he does want me to give him 500 a month, but it's not like he's watching me 24/7, and looking at my balance 24/7 if you know what I mean.