I feel like I'm not going to fund my brother.
Is there something you'd rather spend the money on instead of your brother?
I chose not to fund my brother because I chose to fund my hobby instead
If your brother is an adult, then I totally understand where you're coming from.  Adults should be able to support themselves financially.  He's not your responsibility.
He's a drug addict, who chooses to hurt others.
That's fair enough, and you don't need to take care of someone else if they aren't willing to help themselves first. I doubt that he would even use the money to help himself if he still has a drug addiction.