I don't want to write my brother a good recommendation
Why wouldn't you help your own family out? Has he proven to be unreliable?
I know he's gonna pay me back for this
It's not like it is going to cost you an arm or a leg. You should always try to support your family especially when your brother needs your help. One day you will need his help and he will remember how you didn't help him when he needed you.
I can't talk to him. I'm so pissed that he had the audacity to ask me for help.
If your family is not asking for something that will really put you out there is not reason not to help them. Don't you want to support your family so they can one day help you out?