Hello thank you for your time.
Well, you see I am a US citizen and I am 18. When I was 13 my dad applied for my whole family to become citizens (mother, sister, brother, and me). Sadly because of taxes issues he could only bring my mom, sister, and me. It’s been 5 years since my dad try to apply for my brother's green card. Now that I am 18 I would like to apply for my brother's green card. I make like $10.000 in taxes and I am in college and I don't know if I could start from where my father left off or if I have to start a complete new application. By the way my brother is 23 and he is still not married.

Being able to fully support someone you sponsor is one of the requirements... I doubt a $10,000 income would qualify you.

No, you need to be 21 to apply for siblings.

And even if you could do it, the wait for the siblings category (F4 category) is super long (12+ years currently; even longer for Mexico and Philippines), so it would still have been slower than your father applying for it.

You must be 21.