My cat is very mean. He bites scratches everything! I also know that my 9 year old brother doesn't treat my kitty right. How can I teach him to be nicer to my at? I really don't want to have to get rid of it :'(

First of all, your cat isn't mean - it's a cat. Biting and scratching are normal cat behaviors that cats need to be trained out of.

In order to stop him from biting and scratching you, ignore the cat. If he's on your lap, set him on the floor. If he's on the floor, get up and walk away. Then ignore him. Your cat won't want to be ignored - he thinks he's playing - so eventually he'll learn not to bite or scratch. Don't physically punish him, just... walk away.

Unlike the cat, the brother probably is being mean. You'll either need to keep your brother away from your cat yourself, or enlist your parents for help. That cat is relying on you to keep him safe from harm, even if that harm is your brother, and if you're not able to do that, then you really do need to find your cat a safer home. But first why don't you see if you can come up with away of keeping your brother away from the cat until he learns how to behave himself?