I have an abusive dad but I'm too afraid to do anything
Is your father the one really abusing you?
Not really, but those bruises on my body are from my brother.
If you are being abused you need to tall someone. You do not deserve what it happening to you.
I'm really, really weak.
It is wrong to any adult or person to beat or hit you. Have you tried telling a teacher or calling the police? They can get you out of that situation before it goes on any longer.