I want my dad to do something about my older brother
Why are you telling me?  Do you think you should talk to your dad and brother about this instead?
Research says that talking about an issue helps to solve the problem.
Fair enough. But I think you should be talking about this with your brother and/or your dad. Though there's no guarantee your dad will solve your problem either.
Actually I hate how my dad always favors my older brother over me. It's a big injustice.
I don't know the details, but I would advise against holding onto jealousy against your brother.  This can only cause problems down the line, and it will just upset you.  If your father is not spending enough time with you, try to prompt him to do so.